Picture posting is enabled for all :)
the agreement allows trees but you have to grow under them, which as you say not alot will grow in ground with big roots and lots of shade. if the trees alone counted as cultived then I probably should be OK.
There are things you can grow under a tree, raspberries, for instance. I do think they're being childish, though. If I was in your position I'd complain, either to a councillor or my MP if that failed.
To me it sounds like they're not acting in the spirit of the rules. And making more work for themselves as a result. Surely this is land which has been subsidised by the tax payer to help people grow fruit and veg, and the only reason to start the 75% cultivation rule is to stop people renting it and then covering it with paving and deck chairs. When we look at you, you are using this land as it was intended, to grow fruit and veg. Job done for the council - no need to worry. Why are they fussing about it? ???