I dont know if this is relevant to you BUT a friend of mine spent ages trying to get his outgoing mail working after he moved over to Orange's free broadband.
We were able to setup incoming no problem (yours would be something like mail.fresserve.co.uk or post.freeserve.co.uk or something like that)
The outgoing simply would not work with the SMTP servers we've always used.
Turns out Orange will only let you send mail through their SMTP servers which I thought was odd - They must be scanning all outgoing mail for 'viruses' or othr such stuff......
So your SMTP server would be something like smtp.orange.co.uk - Sorry I can't remember what it is - I'm not on Orange.