With the honourable exception of @agedhorse excellent contributions, everything in this thread, and probably everything on the entire forum has been covered earlier, where do you stop?
WEM stood for 'Watkins Electric Music'.
It looks like 'WML' to me too. Watkins did make guitars, first under the name of 'Watkins' and then 'Wilson'. I don't think the neck plates looked like that, though.
You might find that these need medium scale strings because of the extra distance between the bridge and tailpiece. I've never owned one so I dont' know for sure.
It's a great bit of gear. I only have one Precision so I won't be needing another one, but I'm very happy with the one I've got. I'm also very happy that I can now see the LED thanks to my new Mike Walsh scratch plate. Only thing I'd say is that it would be useful to have that LED as a charge level indicator when the bass isn't on charge.
In Gerrard St. Apparently the song was a reference to it.
Better still, there was one called Ho Lee Fook at the end of the New Kings Road in Chelsea, late 70's early 80's.
I bought some upright bass strings from Jon. It was a perfect transaction, Jon is a pleasure to deal with and very prompt in communications and in sending out the goods. I'd happily deal with him again.
The builders who hang out in the 'Build Diaries' thread will probably give you some pointers. You could try a thread in there, or ask the mods to move this one.
For casters you might find something suitable at Penn Elcom https://www.pennelcomonline.com/
Maybe also corners, though if you have NOS they're probably the thing to go for.
Phil Jones Briefcase has one, so some of his other stuff might do too.
Cue 17-page discussion on whether there is any point to single-knob compression systems.
Some of the apps in mobile phones make use (inadvertently sometimes) of built-in limiters, and may need to be re-calibrated if you want to measure over 100dB or thereabouts.