Premium is only cheaper than Value if you don't have an O2 mobile, but most of use do, as that costs £2.93pm (on a PAYG one, £10 - £1 bonus - 22p vat credit ) and gets £4.89 broadband reduction.

I have email hosted externally and their SMTP server listens on other ports as well as port 25 so it isn't a problem for me. Couldn't you configure yours the same? I have never set up my own mail server so I don't know.