James wrote:

Sorry, forgot this bit: I can't find any rule in Outlook which enables
leaving copies of incoming messages on the server.

There isn't a rule for that. Just like in Outlook Express, it's a property
of the account. You don't state your Outlook version, so, for Outlook
2002/2003, click ToolsE-mail AccountNext. Select your account and click
Change, then More Settings. Select the Advanced tab. It's there. You'll
find it in a similar place in Outlook Express, too.
--
Brian Tillman