Maybe the switch, but to confirm, place nose of vehicle near a wall, and pull the directional lever towards to. Flash-to-pass is high beams...should also light the blue indicator in the speedometer.
Rubber cap? My SU pump has a plastic cover on one end, no rubber cap (but, then, who knows after 47 years if it's original). Toolkit lays in top of spare tyre.....VERY expensive to replace...better off with a small toolbox inside the boot. Wheel and tyre should be no problem to find....even if you have to get one out of Jolly Olde.
There are clips in the front vertical bulkhead of the boot, and under the parcel shelf for jack and crank. The rear window defogger should have been a motor inside the boot blowing through a vent plate in the parcel shelf, if research is correct.
Tip:
Go through the front wheel bearings. Usually, folks just stick a grease gun up to the zerk fitting on the hub, and that just doesn't do the job long-term. I had to almost chisel the dinosaurs out of mine. COUNT THE SHIMS betwixt the caliper bracket, spindle, and steering arm. There are grease zerks on rear axle, one per side, to grease rear wheel bearings. Do NOT over grease or you'll fill your emergency brakes. First time (and you'll know if you have to chisel the garbage off the zerks) 10 pumps, 5 after that should be fine.
Have fun!