Andy Hall wrote:

Having said all of this, a simpler solution to the whole issue may be to
find a mail and DNS hosting service separate from your ISP, register a
domain with it and use that for incoming and outgoing mail.

For some years now I've used 'Virtual Names'
(http://www.virtualnames.co.uk/) run by UK Servers Ltd. With their
'advanced forwarding account' you get up to 10 POP3 mailboxes, with good
configurable spam filtering, webmail access and an SMTP relay for
£10(+VAT) per year. Domains and DNS hosting (& DNS zone control panel)
are also very cheap. Despite the low cost it's a first class service,
reliable and fast. Highly recommended - and I've no connection with
them except as a satisfied customer.

this would depend on whether your ISP allows outgoing port 25
connections to servers outside their world and POP or IMAP connections
similarly. If they don't, then it's time to find another ISP.

Although many mail providers, including the above, accept SMTP
connections on port 225 to get round that problem.

--
Andy