My 1974 88" came with seat belts retrofitted using all Land Rover parts, bolts, nuts and brackets. The inertia reel is mounted to the top of the tub using the L-shaped bracket directly below where the belt passes though the buckle on the factory angle bracket. The stalks bolt into L-shped brackets underneath the tub with captive nuts bolted directly to the chassis.
No need to fabricate anything.
