just pick up the cheapest set they sell in Halfords. Gendarmes wont car if the wrong bulb is in it. If you really want to keep them happy though, get a set with an H1 bulb in it if you haven't done the dual headlight mod or an H4 if you have. That way you will have a dipped headlight bulb with you to change it if needed.
BTW, before anyone jumps up and down, my thinking is, if both dipped bulbs fail, you can replace just the H4 and get one back on.