Hi All

i know this is probably in old threads somewhere but i can't find what
i'm looking for so appologies if this is boring basics for most.
i was under the impression that all showers circuits should be 10mm
cable and 45 amp MCB (or 50 amp if over 10.3 kw)
I am now questioning this because our new/first house is supposed to
have been rewired professionally about 10 years ago and the circuit is
6mm cable with 32 amp MCB (shower is either 7.5 or 8.5 KW. not sure
which as model came in 2 powers and label no longer on shower unit).
This came to light because i want to replace the battered old wall
mounted shower switch located in hallway outside bathroom. Questions
a

1) are cable and mcb ok / comply as they stand?

2) if existing set up is ok but i replaced the shower in future, what
would be the maximum kw rating i could fit while retaining 6mm cable?

3) can i double check that wall mounted shower switches are still ok
provided they are located outside the bathroom, or will i have to
replace with a pull cord switch?

4) am i correct in saying that the amp rating of the new switch i'm
fitting should match that of the mcb? (in this case 32 amp, again
assuming existing set up is ok)

Thanks in advance for any help and taking the time to read this lot!