Hi, Phil.
As Simon says, Yahoo do free pop3, although it is well hidden. I have one in addition to my domain addresses, which I use to sign up to "safe" sites such as pc-pals.
First, make sure you go to
http://www.yahoo.co.uk and not yahoo.com. Sign up for a webmail account. You will then be given a @.co.uk e-mail address. Sign in to the webmail account, go to Options, and you will see a link to enable you to receive pop3. Follow the instructions, making sure (as Simon says) to remove ALL the ticks from the newsletter boxes. The client settings are:
pop.mail.yahoo.com
smtp.mail.yahoo.com
And make sure the box "My server requires authentication" is ticked under Tools>Accounts>Properties>Server.