We (Peter J) & I pushed started a +8 a few years ago at the wicked welsh weekend using the rear luggage rack.
The problem is your at an angle and as the car starts you find yourself falling down.
I still have the scar on my knee..yes, as to push the car you are already leaning forward it is almost impossible not to fall as the car pulls away!
It was a Trad Plus 8, flat battery but enough to operate the fuel pump. It started easily enough!