Well it's been a few weeks, and I've done further research. The GoMog site has a link to
a service manual for the Rover transmissions. It explains how to adjust the gears if reverse becomes very difficult. There is a baulk plate that enables reverse to not be selected accidentally. This can be adjusted by 2 bolts and locknuts that are located below tHe base of the shifter on the right side. It looked like the only access, if the transmission is 'in situ', is from underneath and would have a very tight space to get the wrenches in. On further investigation that would have required some floorboards to be removed, as the underside of transmission is covered by floorboards. Feeling around the transmission cover in the cockpit, it appeared there was a 'plate' under the trim/insulation . So I removed the trim on the right side, and indeed there is a little plate held on by one rivet, so it can be swung out of the way. Unfortunately it gives easy access to one bolt but very limited access to the other. byway, I managed to make the adjustment and loosened up reverse very nicely, but first became tight. To get the job done right, I decided to cut out a small piece of the transmission cover adjacent to the plate. Using tin snips and a Dremel I removed a piece 1" x 1/4", and this gave easy access to both bolts. Adjustment made, and all gears much easier to select. After closing the plate, I used a small piece of duct tape to cover the area that I had cut out. Replaced the trim/ insulation, and it's as good as new.
