Members - re-direct to certain page if not logged in

Hi there

I am using the Members app and everything's going great. I'm assigning a new member a tag automatically and then linking a page to that tag so they have to be logged in to view it.

E.g. you have to be logged in to view the full offer on this page: https://www.lovebedfordoffers.co.uk.gridhosted.co.uk/offers/archive.php?cat=accommodation

If you're not logged in it will direct you to: https://www.lovebedfordoffers.co.uk.gridhosted.co.uk/members/login.php?r=/offers/offer.php

Which brings up the 404 page message.

Please can you let me know the best way so it just re-directs a user to the login/register page on: https://www.lovebedfordoffers.co.uk.gridhosted.co.uk/members/

Thank you