Cannot send email through bt mail server.

Thanks so much to oldk for your post, I really can't thank you enough for posting this. I have had a nightmare with this up until now. Now I can send emails again!

Cheers :-)

Bt don't seem to know anout using a differnt port for SMTP. They blocked port 25 'to prevent spam and fake addresses' and expect everyone to use their BTY server.
I don't intend to use it, in fact I've forwarded BTY POP mail to my domain. But I can't use the BTY SMTP server because my domain is hosted by my last ISP (had to swap when moving as no LLU on present exchange) and their way of preventing spam is to insist that your domain is used to send by SMTP, no relaying. Therefore the two are in direct opposition and I hope that my exchange is at least WBC enabled when my BT contract completes so I can change to a better provider.
I really miss LLU and my last exchange has just been enabled for FTTC. This one doesn't have any LLU or ADSL2+.