Wheelchair Friendly UK Venues

[Jof]

Are there any other wheelchair users on here who can advise on the suitability of various venues for wheelchairs? My only experiences so far are:-
Oulton Park - Poor - there is a disabled parking/viewing area with a plastic cubicle toilet (not clean). Sadly the area is gravelled so self propelled chair users will struggle. The large tarmaced paddock area is good with accessible, clean toilets. Unfortunately, the access roads are also gravelled so hazardous for wheelchairs.

Three Sisters - Poor - disabled parking within the venue but you have to struggle through gravel to get to somewhere you can see anything. There is a disabled viewing area but it is up a steepish ramp so self-propellors might struggle. The disabled toilet is accessed accross a gravelled area and up a steep ramp - you will need to get someone to help you if you need to go the loo. The paddock area is mostly tarmac.

If anyone can advise on other venues' suitability, I would be grateful. Anywhere you don't have to negotiate gravel would be marvellous!
Thanks,
Jo