On Saturday, 29 August 2015 20:34:07 UTC+1, Tough Guy no. 1265 wrote:
I don't what the English rules are, but up here in Scotland we don't do
certificates, especially not for just fitting a shower.

The rules, i.e. BS7671 Wiring Regulations or an equivalent level of safety, are the same in Scotland and England.

Notification to Building Control is slightly different, but the requirements for wiring are the same.

Owain