Sorry for confusion: I refer to BT mail as the BT Yahoo service which came with my package and which I use with Thunderbird. This is the one which acts up on occasion for no discernible reason.
I also have a (separate) yahoo.co.uk account which has proved totally reliable.
Please ignore my post above, I didn't read to the end of page 1 before posting !
Garyilka (knowledge is power)
Fri 14-Dec-12 16:29:13