It appears that NTL are discarding any emails received from - or via - any host registered in the SORBS database. Currently we are unable to receive any email from beeb.net or lycos.co.uk. I understand that this is happening with webmail.co.za as well.
I have made a strong complaint to NTL about this, as it is causing my wife severe inconvenience. She is secretary of a choir, and all emails to her from the musical director and another member of the committee are being silently discarded.
Personally I think that this heavy handed policy stinks, and now that NTL have spam detection software it really isn't necessary anyway.
If/when I receive a reply from NTL I'll try to remember to post it here.
Brian