Red, blue, yellow and bare earth, surely?The wires in the ceiling are red, blue, yellow.
No, red, blue and yellow, no bare earth.
Green?They change to brown, blue, green between the switch and the fan.
Really?
Yes, brown, blue and green, although on closer inspection the green does have a yellow strip on the back.
I'm afraid I don't know what type of shower it is. Hot water pipe from the boiler to a mixer valve then up to a shower outlet overhead. Sorry I can't be more specific!