Well I've finally done the rear gearbox mount countersunk bolts conversion. I tried jacking front of car and also the rear (separately). Not enough clearance under the middle of the car. I eventually jacked the side of the car (with two trolley jacks). I learnt a few lessons and anyone wanting to do this without a lift or a pit I'm happy to give them the benefit of my experience. Due to not having a large enough countersink bit the bolt heads are slightly proud but its a big improvement.
