Good choice, but assuming it is a new circuit, then you need to speak the Competent Scheme Electrician before you actually start the work.ok, looks like its a 40 Amp MCB, will get the work certified, this is a requirement by the housing association.
Even if it is just replacing an old shower then it is still worth speaking to him before you start.
I know you are in Wales and different rules apply - but most housing associations I deal with just want an Electrical installation certificate, showing that the replacement shower has been fitted and tested to BS7671.