Thanks for your input guys we have fabricated a gearbox mount using a type 9 mounting and extended it and bolted through the floorpan to h duty steel plate with bolts made captive on it so it just needs the nuts taking off from underneath to get the box out.
We reckon the type 9 and T5 gearboxes are about the same length, the problem arose because it previously had a rocket box in it. As part of the restoration we fabricated a large gearbox tunnel so we had no problems with clearance. The propshaft had to be shortened by 55mm.
The box and prop are now in place we have gone for an hydraulic handbrake next to the gear lever as when the seat is in if the handbrake lever is moved further back I will not be able to give it a good tug. We may locate original handbrake further back or shorten the lever on it to retain a cable handbrake as per MSA regulations