Have I just confused myself??
Yes.
If you are maintaining VMC then you can't be IMC. If maintaining 'sight of the surface' isn't a VFR requirement for the situation you are in, then you don't need to maintain that requirement to maitain VMC
It would be legal to fly at 2000' above total cloud cover where the cloud tops are 1000', so long as you have 5km viz.
Having said that, flying around over complete cloud cover where the cloudbase is low, or at the surface, is not something to be taken lightly. (As I'm sure you are aware, and from your original post it sounds like you were thinking about all the right things.)
MJ
