Re: TRITON Biarritz 2 shower fault
Whilst your shower may be white, it does not come under the remit of ‘whitegoods’
That said I have changed the solenoid valve and the flow valve on my Triton shower in the past, however this is not really the place for your question.
It does sound as though you may have a wiring fault, possibly dodgy neutral connection in the isolation switch or inside the unit.
I would advise seeking out a local electrician.
Jim.