I had no trouble on either front as the VIN was the same, the engine the same just some bodywork had gone away. You'll have to tell the insurer and most 'normal' insurers won't touch you but the specialists seem OK on it. I didn't need an engineer's report which some places seem to think is required.
So I wouldn't expect any drama! Of course it helps if you go to an MOT station that knows about off roaders.