Sorry to hear that, but it does sort of come with riding a bike...
I presumed he would be thrashing around on his own and that road legal was good enough (plus plugs, as Adrev so rightly says, I've seen a core sample of a thigh taken at Brands Hatch years ago!).
Yeah just read the T&C and it says; 2 working brakes and bars should be taped/grips with bar ends .. so i guess just a bar end plug and rear brake away ..
Still not legal (Lee Valley Velopark = LVV)
If they have same rules as the races .. there was a crash last weds during the open session