My first few novice club races late 80's were push start and pretty sure the MGP was clutch then oddly TT was push(I think) ... my crisp pokey TZ350 was a doddle to start, on a workshop stand I could start it with a mate pulling / rotating the back wheel and me quickly flicking / dropping the clutch in/out.....hazy memory tells me that Snetterton was uphill, Castle Combe / Cadwell fairly level on the grid.