I don't have or use an iphone, but it sounds like the cookies are being deleted once you close your browser. Is there a setting for that?
Otherwise, I can't help - other than say get an Android-based phone.
Thanks very much for your responses guys.
Ironically I couldn't log on earlier, to post my thanks!
It looks like it is the cookies, cos the "accept cookies" option was set to "never" rather than "always" or "from visited" - so thanks kinboshi
It used to work ok, so I musta changed that setting recently (by accident obv).
Ta muchly
Drainy