Start with the type of shower
An electric shower, a mixer supplied by a boiler and a pumped system need different checks. Send the make and model and explain whether the problem affects temperature, flow or a visible leak. Electrical faults and any electrical installation work require the appropriate competence and a separately agreed scope.
A compatible replacement matters
The existing pipe centres, wall depth and hot-water system influence which fitting will work. A concealed valve may need tile removal to change its body. Replacing the visible trim alone is only an option when the manufacturer confirms compatibility with the installed valve.
Protect the wider bathroom finish
Shower leaks can involve pipe connections, waste fittings, trays or surrounding finishes. Identify what will be investigated and whether waterproofing, resealing, tiling or access-panel work is included. We can quote for the agreed plumbing and explain where another trade is needed.

