Hi Jim,
I'm just flagging this one to Bob for perusal.

Thanks Jim,
I suspect this is part of the ongoing issues we've been seeing. I've added your details to the problem (46314) and should be updating the Service Status thread later on today.
AFAIK, it's something to do with one of the Clam processes on the delivery servers. This process needs to interact with a log script, and on a couple of occasions each day for a very short period of time the communication between the two fails. This causes the odd email to become 'stuck' like with one of the examples you have provided.
I'll try and expand on that a little if I can once I know the latest.
Edit: Can you PM me the actual address the email was sent to so we can check the logs?
Edit again: Service Status update now posted.

Not a huge delay (about an hour) but:

Quote

X-Daemon-Classification: INNOCENT Envelope-to: firstbit@mydomain.co.uk Delivery-date: Wed, 26 Sep 2007 09:11:26 +0100 Received: from fk-out-0910.google.com ([209.85.128.185])   by pih-sunmxcore13.plus.net with esmtp (PlusNet MXCore v2.00) id 1IaRB1-0005Q5-MG   for firstbit@mydomain.co.uk; Wed, 26 Sep 2007 08:19:20 +0100

OldJim - I would edit out your email address if I were you....

Well spotted - corrected.

Here is one that was sat on by MXcore19 for six or more hours.
[tt]Delivery-date: Wed, 26 Sep 2007 18:31:08 +0100
Received: from fwd0.hosts.co.uk ([85.233.160.22])
  by pih-sunmxcore19.plus.net with esmtp (PlusNet MXCore v2.00) id 1IaURh-0007Mu-B1
  for ***@***.plus.com; Wed, 26 Sep 2007 11:48:48 +0100
Received: from [212.135.6.55] (helo=apache4-wm.uk.easynet.net)
by fwd0.hosts.co.uk with esmtp (Exim 4.63)
(envelope-from <***@ukonline.co.uk>)
id 1IaUOr-0005MW-5A
for ***@***.org.uk; Wed, 26 Sep 2007 11:45:49 +0100
Received: from www by apache4-wm.uk.easynet.net with local (Exim 3.36 #1)
id 1IaUOp-000FQV-00
for ***@***.org.uk; Wed, 26 Sep 2007 11:45:47 +0100
Received: from 217.205.243.132 ([217.205.243.132])
by webmail.ukonline.net (IMP) with HTTP
for <***@localhost>; Wed, 26 Sep 2007 11:45:47 +0100[/tt]

Email queues are up.
Before anyone blames this on no longer doing the dynamic IP blocking, you have to look back to the period before the blocking was implemented.
The queues before the blocking were the same size as those during the blocking period. At both times the queues were a lot lower than they are now.

I received a mail,  posted at 2239 on the 24th, at approx. 2000 on the 25th. A 22hour delay.

-------- Original Message --------
From: - Tue Sep 25 19:28:52 2007
X-Account-Key: account2
X-UIDL: UID1914-1064685910
X-Mozilla-Status: 0005
X-Mozilla-Status2: 10000000
X-Mozilla-Keys:
X-Daemon-Classification: INNOCENT
Envelope-to: mail@xxxxxxxx.plus.com
Delivery-date: Mon, 24 Sep 2007 22:39:24 +0100
Received: from mail12.bluewin.ch ([195.186.19.61]) by pih-sunmxcore16.plus.net with esmtp (PlusNet MXCore v2.00) id 1IZvdj-0005tt-HF for mail@xxxxxxx.plus.com; Mon, 24 Sep 2007 22:39:23 +0100
Received: from janapc (85.2.61.83) by mail12.bluewin.ch (Bluewin 7.3.121) id 46F37EFC000AD15A for mail@xxxxxxxx.plus.com; Mon, 24 Sep 2007 21:38:27 +0000
Message-ID: <009501c7fef2$c07ee1b0$6401a8c0@janapc>
From: xxxxxxxxxxxxxxxx
To: xxxxxxxxxxxxxxxxx
Subject: Photos
Date: Mon, 24 Sep 2007 23:34:53 +0200
MIME-Version: 1.0
Content-Type: multipart/mixed; boundary="----=_NextPart_000_0091_01C7FF03.822D4C60"
X-Priority: 3
X-MSMail-Priority: Normal
X-Mailer: Microsoft Outlook Express 6.00.2900.3138
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3138
X-PN-VirusFiltered: by PlusNet MXCore (v4.00)

Quote

X-Daemon-Classification: INNOCENT Envelope-to: xxxxx@xxxxx.co.uk Delivery-date: Thu, 27 Sep 2007 04:41:45 +0100 Received: from web01.swreg.org ([209.87.181.114] helo=dc1swweb04.swreg.digitalriver.com)   by pih-sunmxcore16.plus.net with esmtp (PlusNet MXCore v2.00) id 1Iada1-0005yn-GN   for xxxxx@xxxxx.co.uk; Wed, 26 Sep 2007 21:33:57 +0100

6 hours delay

hate to say this, but I can do better than 6 hours
How about 4 days for this one..
X-Symantec-TimeoutProtection: 0
X-Daemon-Classification: INNOCENT
Envelope-to: roger@xxxxxxxx.plus.com
Delivery-date: Tue, 25 Sep 2007 21:13:55 +0100
Received: from [67.15.127.26] (helo=forumup.co.uk)
  by pih-sunmxcore11.plus.net with smtp (PlusNet MXCore v2.00) id 1IaGn5-0004Ge-Bo
  for roger@xxxxxxx.plus.com; Tue, 25 Sep 2007 21:13:55 +0100
Received: (qmail 21471 invoked by uid 48); 21 Sep 2007 13:48:33 -0000
Date: 21 Sep 2007 13:48:33 -0000
Message-ID: <20070921134833.21470.qmail@forumup.co.uk>
To: roger@xxxxxxx.plus.com
Subject: =?UTF-8?B?R2V0IEZvcnVtIEJhY2t1cA==?=
From: webmaster@forumup.co.uk
Reply-To: webmaster@forumup.co.uk
Content-Type: text/plain; charset=UTF-8
X-PN-Spam-Filtered: by PlusNet MXCore (v4.00)
X-DSPAM-Result: Innocent
X-DSPAM-Processed: Tue Sep 25 21:13:56 2007
X-DSPAM-Confidence: 0.7502
X-DSPAM-Improbability: 1 in 301 chance of being spam
X-DSPAM-Probability: 0.0000
X-DSPAM-Factors: 27,

And... 5 days for this one....
X-Daemon-Classification: INNOCENT
Envelope-to: roger@xxxxxxx.plus.com
Delivery-date: Tue, 25 Sep 2007 21:59:58 +0100
Received: from [67.15.127.26] (helo=forumup.co.uk)
  by pih-sunmxcore13.plus.net with smtp (PlusNet MXCore v2.00) id 1IaHVd-0003ZT-A4
  for roger@xxxxxxx.plus.com; Tue, 25 Sep 2007 21:59:57 +0100
Received: (qmail 15013 invoked by uid 48); 20 Sep 2007 10:07:55 -0000
Date: 20 Sep 2007 10:07:55 -0000
Message-ID: <20070920100755.15012.qmail@forumup.co.uk>
To: roger@xxxxxxx.plus.com
Subject: =?UTF-8?B?R2V0IEZvcnVtIEJhY2t1cA==?=
From: webmaster@forumup.co.uk
Reply-To: webmaster@forumup.co.uk
Content-Type: text/plain; charset=UTF-8
X-PN-Spam-Filtered: by PlusNet MXCore (v4.00)
X-DSPAM-Result: Innocent
X-DSPAM-Processed: Tue Sep 25 21:59:58 2007
X-DSPAM-Confidence: 0.7515
X-DSPAM-Improbability: 1 in 303 chance of being spam
X-DSPAM-Probability: 0.0000
X-DSPAM-Factors: 27,

It's a good job there weren't critical emails, and now this is having me seriously question the reliability of your new MXcores- Perhaps I should just join the queue!

Sorry rogerloxton, but I don't think they count.
They were not delayed by PlusNet, since PlusNet received them and delivered them to you within seconds.
It was qmail that delayed them:

Quote

Received: from [67.15.127.26] (helo=forumup.co.uk)     by pih-sunmxcore11.plus.net with smtp (PlusNet MXCore v2.00) id 1IaGn5-0004Ge-Bo     for roger@xxxxxxx.plus.com; Tue, 25 Sep 2007 21:13:55 +0100 Received: (qmail 21471 invoked by uid 48); 21 Sep 2007 13:48:33 -0000

forumup.co.uk only passed this one on to PlusNet on Tue, 25 Sep 2007 21:13:55  even though you sent it 21 Sep 2007 13:48:33.

heres mine:
X-Daemon-Classification: INNOCENT
Envelope-to: xxxxxxx@.plus.com
Delivery-date: Thu, 27 Sep 2007 08:11:59 +0100
Received: from ([211.115.216.226])
 by pih-sunmxcore15.plus.net with smtp (PlusNet MXCore v2.00) id 1IanX3-000010-HM
 for xxxxxx@.plus.com; Thu, 27 Sep 2007 08:11:59 +0100
Received: from xxxxx.xxxxx.co.uk ([62.72.52.62])
by BFLITEMAIL-KR3.xxxxxxx.com (LiteMail v3.03(BFLITEMAIL-KR3)) with SMTP id 0709251135_BFLITEMAIL-KR3_1012528_13451322;
Tue, 25 Sep 2007 11:36:25 -0400 EST

Sorry keerto1, I don't think yours counts either.
According to the header information, it was only delivered by the "Korea Network Information Center" [211.115.216.226] to PlusNet on Thu, 27 Sep 2007 08:11:59 and was delivered straight away (one second).

Bizarre, as I picked up late last night another email which was sent on monday:
X-Daemon-Classification: INNOCENT
Envelope-to: xxxxxxx@xxxxxx.plus.com
Delivery-date: Wed, 26 Sep 2007 19:40:05 +0100
Received: from mail-kr.xxxxxxxx([211.115.216.226])
  by pih-sunmxcore16.plus.net with smtp (PlusNet MXCore v2.00) id 1Iabnj-0004oQ-0s
  for xxxxxxx@xxxxxxx.plus.com; Wed, 26 Sep 2007 19:40:04 +0100
Received: from mx0.centricnetworks.net ([213.166.11.5])
by BFLITEMAIL-KR3.xxxxxxx.com (LiteMail v3.03(BFLITEMAIL-KR3)) with SMTP id 0709240803_BFLITEMAIL-KR3_1011839_38541444;
Mon, 24 Sep 2007 08:04:27 -0400 EST
Received: from xxxxxxxxxx.co.uk (unknown [213.232.76.36])
by mx0.centricnetworks.net (ESMTP) with ESMTP id 0CF14183E6B
for <xxxxxxxxxx.com>; Mon, 24 Sep 2007 13:04:13 +0100 (BS

I know that I use a mail forwarder but its never been that slow and its coiciding with plusnets email delays