Adrian, you appear to be in a tactically defensive position?
Colin, I have done recon work on a ferret trans and assembled a couple of bevel boxes, however I have not been (un)fortunate to have tried working on a broken down Ferret. I have yet to see in British historical photos, images of mechanics hanging by their feet while working on carriers and tanks. I do remember (a picture in a manual) of the Leyland man holding a Leyland 680 cylinder head at arms length while lowering the head (there are two) onto the block. My back trouble probably stems back to TK bedford head work. A much more viable proposition. I digress (again!)
Back to your master craftmanship on the VLT. On your hydraulic drives. I assume you do calcs. to work out what your ground speed might end up at?