Note that the screws through the bracket and engine front-plate this side of the car are countersunk and the nuts are stiff-nuts. The top one is completely covered by the rubber mount so you may need to lift the engine and remove the rubber mount to be able to hold the screw whilst removing/refitting the nut. The lower one is out past the rubber mount so may be accessible, which may be why the Bee's strap is under the lower nut. Because of the shape of the engine (there is more space between the block and the off-side engine mount) the mount bracket is the other way round so standard bolts heads are accessible. The Parts Catalogue shows stiff-nuts on all four.

Rubber bumper round a gearbox mount, using a mount to gearbox bolt and mount stud to crossmember nut. Note this shows it fitted to the left-hand side front, which is how I found it on Vee, the manuals show it on the right-hand side front:

However it only belatedly struck me that this strap only connects the engine and gearbox to the crossmember. The crossmember still has to make a good connection to the chassis rails, and with a super-sonic paint job on both that will have to be from the bolt spring washers cutting into the crossmember and the threads inside the chassis rails which go into captive but sliding threaded plates.

Charles9 in the UK posted this picture of his 1980 model owned from new which has an engine earth strap from the oil gauge connector mounting bolt on the heater shelf to an engine back-plate bolt. Clausager references this change at chassis number 515195 roadster and 516743 GT in April 1980, which puts it at only 8000 or so cars from the end of production or less then 2% of the total!

Probably easier to add this to other RB models (except V8s) rather than nearer the front from an alternator or even a starter bolt to the inner wing or chassis rail.

5-speed conversion:
Oddly Vitesse Global Ltd. don't fit a ground strap with their gearbox even though V8 and RB conversions removes the factory strap, although they do recommend one. How it earths I don't know as with the factory strap missing on the standard gearbox cranking is quite badly affected and various wires and cables get hot and smoke. Whilst Vee did seem to be cranking OK I checked and found I was losing about 1.3v, so after some thought as to position I fitted one and the volt-drop was reduced to 0.1v so well worth it.