I concur with Eden.

The UK army rarely works at corps level (having only the one Corps HQ) and equally rarely within an understood corps context. When our div HQs exercise the scenario inevitably focuses on them (to run them out) and when they train for deployments (Afghanistan or Iraq) I suspect they see Corps HQs as their higher HQs without understanding the corps level of operations. My perspective from Iraq is that Div staff did not understand what Corps could do for them in terms of flexing resources, nor how Corps managed the campaign.

I would also say that Corps is the level where multinationality works well, at Div it is okay and (from personal experience) at brigade level it sucks.