Emails from whitelisted sender being sent to SPAM

[#1]

in my whitelist i have    email.royalcaribbean.co.uk
In my SPAM box i have email from that address.
How did it get there?
Message headers:-
Return-path: <bounce-134484_HTML-687787819-6173740-1353164-558@bounce.email.royalcaribbean.co.uk>
Envelope-to: xxxx@yyyy.plus.com
Delivery-date: Thu, 16 Jul 2015 17:29:14 +0100
Received: from [212.159.9.108] (helo=avasin18.plus.net)
  by inmx10.plus.net with esmtp (PlusNet MXCore v2.00) id 1ZFm25-0007Fw-RM
  for xxxx@yyyy.plus.com; Thu, 16 Jul 2015 17:29:13 +0100
Received: from mta.email.royalcaribbean.co.uk ([198.245.88.110])
by avasin18.plus.net with Plusnet Cloudmark Gateway
id t4V91q00K2NqwdS014VC5m; Thu, 16 Jul 2015 17:29:13 +0100
X-BV-Spam-Flag: Yes
X-IPAS: Level1
X-CM-Score: 100.00
X-CNFS-Analysis: v=2.1 cv=OelldUnY c=1 sm=1 tr=0 b=1 p=1N86r9cjAAAA:20
a=0DBHzfzG+d8I74VHlT2Mmg==:117 a=0DBHzfzG+d8I74VHlT2Mmg==:17 a=KoooV4uDAAAA:8
a=0Bzu9jTXAAAA:8 a=zOBTXjUuO1YA:10 a=r77TgQKjGQsHNAKrUKIA:9 a=gZbpxnkM3yUA:10
a=EBOSESyhAAAA:8 a=6oD-6IY4tXnNdmAeQjEA:9 a=40AEzjylhXFO16kA:21
a=2F57__PQXw_P2nat:21 a=QEXdDO2ut3YA:10 a=JGHSkcQMkysA:10 a=qxQYXEKkbJwA:10
a=IdqrlHSnAAAA:8 a=SSmOFEACAAAA:8 a=2jx82orhRI-IfOtoqi8A:9
a=zKfLsi8Z9_LKwuP7:21 a=LwaO-M9ufJVziLLA:21 a=E44BkeotzYwZS544:21
a=_W_S_7VecoQA:10 a=frz4AuCg-hUA:10 a=Ok_V0Hfu_skA:10 a=MZpOI37Du90A:10
DKIM-Signature: v=1; a=rsa-sha1; c=relaxed/relaxed; s=200608; d=email.royalcaribbean.co.uk;
h=From:To:Subject:Date:MIME-Version:Reply-To:Message-ID:Content-Type; i=royalcaribbean@email.royalcaribbean.co.uk;
bh=n5Rxsw4PbipGfv7y46oDf3SUuk4=;
b=BWkCh4I/u9mpVDE+bM9BD2I+c45PQXI0Dm7PtlYqJyDuwGPunsMEyvCf5tUpgi2VzKh7zCqN7iTt
  BT9qP1pzOYFi9EGMIlrL7UdBl/0T3KnS8y0NiwVVfu8GjmmTEITaD1hBjTsEH6eBTu2OVeL+zIGi
  /YFh9bLn2ZZ34kqXa/E=
DomainKey-Signature: a=rsa-sha1; c=nofws; q=dns; s=200608; d=email.royalcaribbean.co.uk;
b=jga53gOnsYjmy6dvENjKUDEghcX3hLjkjW/w2jrE1gspqSWeX+be1s+Sq4cLcfdHLFTRz8EQiWCd
  Npf2UN3QXf8VcVYXvsPJJTAgzFgd3V0KCOLFIilkYJxEoH57hqmX5xY/lnghlxMPgF0JSvYPaTUK
  EhofdjYE1ELGpJXkiBY=;
Received: by mta.email.royalcaribbean.co.uk id hkvdtg163hsj for <xxxx@yyyy.PLUS.COM>; Thu, 16 Jul 2015 09:12:18 -0600 (envelope-from <bounce-134484_HTML-687787819-6173740-1353164-558@bounce.email.royalcaribbean.co.uk>)
From: "Royal Caribbean International" <royalcaribbean@email.royalcaribbean.co.uk>
To: <xxxx@yyyy.PLUS.COM>
Date: Thu, 16 Jul 2015 09:12:17 -0600
MIME-Version: 1.0
Reply-To: "Royal Caribbean International" <reply-fe9312717267037975-134484_HTML-687787819-1353164-558@email.royalcaribbean.co.uk>
x-job: 1353164_6173740
Message-ID: <925e6cd1-92b7-445c-8570-e2b891ae6cbd@xtnvmta1391.xt.local>
Content-Type: multipart/alternative;
boundary="AVLZDK95csI5=_?:"
X-pn-pstn: Spam 1
X-PN-Virus-Filtered: by PlusNet MXCore (v5.00)
X-PN-Spam-Filtered: by PlusNet MXCore (v5.00)
Subject: Sail from UK with up to $400 onboard spend on us available on selected sailings

[#2]

Was this email sent to your .plus.com address or your domain? If it's the latter, then you don't have a whitelist entry for the domain.
If it's the former, then I believe you need to create an entry based on the envelope-from domain:

Quote from: cjags

Received: by mta.email.royalcaribbean.co.uk id hkvdtg163hsj for <xxxx@yyyy.PLUS.COM>; Thu, 16 Jul 2015 09:12:18 -0600 (envelope-from <bounce-134484_HTML-687787819-6173740-1353164-558@bounce.email.royalcaribbean.co.uk>)

Which is bounce.email.royalcaribbean.co.uk.

[#3]

Quote from: Bob

...  you need to create an entry based on the envelope-from domain: ..... Which is bounce.email.royalcaribbean.co.uk.

Surely, the domain "royalcaribbean.co.uk" should cover the sub-domain "email.royalcaribbean.co.uk" and the sub-sub-domain "bounce.email.royalcaribbean.co.uk"

[#4]

That's not how it works.

~$ telnet mx.avasin.plus.net 25
Trying 212.159.8.200...
Connected to mx.avasin.plus.net.
Escape character is '^]'.
220 avasin09.plus.net Plusnet Cloudmark Gateway ESMTP server ready
ehlo avasin
250-avasin09.plus.net hello [84.93.219.165], pleased to meet you
250-SIZE 104857600
250-8BITMIME
250 OK
mail from:<test@test.com>
250 <test@test.com> sender ok
rcpt to:<test@bobpullen.plus.com>
550 <test@bobpullen.plus.com> Address or domain has been blocked by recipient

~$ telnet mx.avasin.plus.net 25
Trying 212.159.9.200...
Connected to mx.avasin.plus.net.
Escape character is '^]'.
220 avasin10.plus.net Plusnet Cloudmark Gateway ESMTP server ready
ehlo avasin
250-avasin10.plus.net hello [84.93.219.165], pleased to meet you
250-SIZE 104857600
250-8BITMIME
250 OK
mail from:<test@subdomain.test.com>
250 <test@subdomain.test.com> sender ok
rcpt to:<test@bobpullen.plus.com>
250 <test@bobpullen.plus.com> recipient ok

[#5]

So when adding to the whitelist, I should use the envelope-from: value not the From: value?

[#6]

Yes, that should work.

[#7]

To be sure, I have added both.