The shower pull cord isolation switch has been wired incorrectly, which is concerning because a professional person would know that it is important that any switch with a neon light on it
LGA Selectric LG954N 1 Gang 45 amp double pole ceiling shower pull switch with neon : Amazon.co.uk: DIY & Tools
CEDCLS45N 45A Shower Pull Switch
Powerplus 45A White Shower Pull Cord Ceiling Heavy Duty Switch Double Pole
SHOWER PULL CORD SWITCH DOUBLE POLE BATHROOM EXTRACTOR FAN CEILING NEON 45A | eBay
Knightsbridge SN8310N White 45A Pull Cord Switch,Double Pole : Amazon.co.uk: DIY & Tools
LAP H8187N 50A 2 way Pull cord switch
David Savery Electrical Services Ltd. - Top tip: Shower Isolators