wrote:

At one point the BT support droid said "well in that case, Connectfree
will have to provide you with your own smtp server"

You can buy email services from someone else.

Many web hosting companies provide them with their hosting accounts but
check if an SMTP server is part of the deal. For example 1&1 have it,
123-reg don't.

http://www.authsmtp.com offers a paid for service (I've used it - it's
OK). Google also offers a free SMTP server.

Setting up your own SMTP server means that you be forever wondering
whether your domain has been blacklisted when outgoing mail hasn't been
received by the persons you are sending to. Having it on a IP connection
called 'BT broadband' is not going to help in that respect - that
service is a known dwelling of zombie trojan infected spam spewing
'family PCs'.

--
Adrian C