Hi Nige,
Got your mails. Will investigate tommorrow if anything weired is there as it is 3 AM here now. Also, I don't think i'll be able to provide much help in case of BT as I don't know about their policies etc. However, I will still look at the mails and see if anything needs correction.
The temp folder I'm referring to is at the sender's server. But in that case the bounces should have come from postmaster or mailerdaemin at server.eukhost.com not the recipient. From a bitds eyeview it appears they(BT serviced by yahoo) could be in the process of taking antispam measures where rules have to be set. Your mails could be boucing due to conflicting rules or are being "defered" for local reasons such as unable to deliver to the recipient because the message could not be filtered during the set time of, say, 4 hours (you will receive a failure after 96 hours typically).
Your mails were received in no time on all my accounts. And a quick look at headers reveals everything seems to be OK. So no server issues as such.
But will see in the morning and update accordingly. Never mind the drone comments
we are all in the same boat when it is stormy.
Regds
IJ