I want to replace my existing power shower (installed in 1999) with the current version of the same model from the same manufacturer. No changes are required to the plumbing, but the manufacturer recommends that I replace the exisiting electrical transformer with the one that comes with the new shower. This will require hard wiring the mains cable from the transformer to the exisiting mains switch (in place of the mains cable from the old transformer).
Is this work that falls within Building Regulations (i.e. requires a Part P certified electrician to carry out/inspect the work)?