I had the same issue as you, when I fitted the corner bars/over-riders it was where the fog lamp and reversing lamp was, so I initially moved mine to the very outside corners of the valance.

I had it like that for a year and a bit, it was alright except that all the mud and crap that gets flung up from the road by the rear tyres was being deposited on to the back of the lights, which wasn't doing them any favours... style wise I'm not sure looking back at it, because it sort of covers up the nice curve of the arches where they blend in to the valance.
So in the summer I put them more in the middle, like this:

I would have put them further out towards the edges, but the exhaust restricts where the reverse lamp goes and I wanted them to be symmetrical of course, so settled on that.
Personally, I'd just be putting the fog in the centre on your car and not bothering with the reverse light unless you were going to install Mk1/Mk2 lights, seeing as your later lights have the reversing lights in the cluster anyway.
Edited by The Otter, 06 December 2012 - 06:19 PM.