Thank you - Yes I really hope that the BB is compatible with my cranks and frames - it should be but I guess I won't know until I try.
I'm located in Berlin, Germany so prob not a ton of forums members here, doubtless there is a german language forum that I should post on.

It looks like finding a fixed cup wrench in 35mm size is not so easy, I see several on Ebay for like 40 bucks in USA but it's not practical to ship anything from there these days.

I think I need the park tool HCW-2 or something equivalent. Perhaps I'll try to see if one of the local shops will let me borrow one but I doubt it.