Does anyone know the type of bulb used for the warning lights in the clocks and the lighter socket surround on a pre fird BA?

It's not a 501, it's the tiny one that fits similarly! That doesn't help much I know!

Possibly a 286?

The fag lightern one does look like a 286 doesn't it

I think so yeah, and the warning lights behind the dash (aswell as the hazard/demist lights, headlamp level light - all of those) are also that same size

Cant help here, but I was thinking that there should be a 'guide' to bulbs and fitments in the guide section. People can add to it when they find out or need to change one?

I'll do one once I've replaced all my bulbs