The timber will probably be 195 x 45.
I think it is good to centre the steel plate top-to-bottom so it doesn't bear directly on the timber above / below.
I think this may be a struggle to source.
Yes I saw those and they look v good value compared to the commercial stuff from plasson etc but we are in a tight space and the plumber suggested Ts from a 28mm. I know not much about plumbing but thought if the purpose designed one leaks you would need to replace the whole thing where with normal fittings maybe not.
I imagine it is fine but we are feeding 8 flats. We have a new 32mm MDPE supply so we are thinking 28mm copper with 28mm x 28mm x 15mm reducing tees to each of the meters. The 28mm will also have a cold water accumulator. Current setup is 15mm spaghetti, so electric showers tend not be too impressive.
I use a dehumidifier to dry washing in a small utility with no window. Normally I don't have the extractor on.
The cable through the wall plugged into a socket the other side is fine, especially if you don't need the dehumidifier elsewhere.
Is it the case that the planners will not let you demolish this? It is certainly not pretty. It does have a pyramid vibe though so you could decorate with hieroglyphics.
It sounds like you are renting the flat which would mean asking your landlord to sort this out.
He should have ensured that the adjacent owners had the ceiling replaced with one of at least the same fire and acoustic performance.
It is hard to say for certain but it looks like the steel supports are structural. Was this 2 openings? The outside post looks fairly corroded. I think a structural engineer would be best placed to advise.