Good points, DP. I had not considered 1000ft from cloud up and down.
I am under the impression (probably wrongly) that when VFR one flies quadrantal on QNH and IFR on 1013. I agree that for the purposes of collision avoidance that is a bit daft!
Thanks Bookworm, for the purpose of this discussion I am more interested in "sensible" rather than legal! Not that I would ever do anything illegal, of course.