Brake light switch problems

[nwxh]

I'm not sure quite what you're referring to, but I assume you mean the two screws on the drum face that screw into the hub, to hold the drum to the hub. Ideally two are needed, though I've seen some with one or no screws fitted.
The hubs should not need to be replaced unless damaged by a spun bearing or similar, the bearings can and do fail though, this should be checked with the wheel jacked up. The cylinders need replacing if they are leaking or seized/seizing, otherwise I'd leave them as their quality is likely to be better than modern reproductions.
Nipples shouldn't need changing unless damaged (rounded off?) either, but if you fit a new cylinder, you should use the nipple supplied with it (if included).

Cheers. I thought these were adjusting screws, and one is missing. On looking at the diagram in the manual, it appears they are what you refer to.

[bmcecosse]

It's been a struggle- but hopefully you now have working barkes and lights. As above - these screws don't matter.... One is plenty.

[nwxh]

Many thanks again! Will ensure the brakes are working tomo evening.

[nwxh]

Everything seems to be in working order.

[bmcecosse]

Well done !