Multiple email now banned?

[#1]

I run a reading group with 7 members and I send out a reminder before each meeting.
Today's reminder appears to have got lost -- it is sent to me as well.
When I saw that I hadn't got my copy I sent an email to the group asking if they'd got their copies -- I didn't get a copy of this either.
I usually get my copy pretty well immediately -- I thought, perhaps, it knew HMV... no longer, it seems.
I use Postfix to send emails.
The log entry for my email is
Mar  7 12:39:06 mistakenot postfix/smtp[4439]: 20DCB2F4086: to=<cmartin@spamcop.net>, relay=relay.plus.net[212.159.8.107]:25, delay=1.8, delays=0.38/0.07/1.1/0.27, dsn=2.0.0, status=sent (250 acf51n0040bjmnl01cf62Y mail accepted for delivery)
and for the second one
Mar  7 19:05:21 mistakenot postfix/smtp[3954]: C2E1B2F4086: to=<cmartin@spamcop.net>, relay=relay.plus.net[212.159.9.107]:25, delay=2.6, delays=0.31/0.09/2.1/0.13, dsn=2.0.0, status=sent (250 aj5L1n0020bjmnl01j5Me2 mail accepted for delivery)
Chris

[#2]

Hmmm, with the passing of time and the cessation of steam being emitted from my ears, it has occurred to me that it probably is SpamCop that is not sending on my emails.
I have asked my daughter to send me an email to check, she has sent two and they have not arrived.
I shall have to buy stamps ...
Chris