Leaking Galaxy 2000 Aqua shower

[gnvqsos]

I have a defective shower which was fitted for a customer,where water is leaking internally,and am wondering what has caused this.Possible explanations are
1.failed PRD
2.blockage of outlet
3.failed internal seals
I believe the problem is a result of misuse and the customer attempoted a repair before notifying me,removing the cover and failing to isolate power at consumer unit.I was seeking advice as I generally replace older showers with a new model.This unit nwas 3 years old

 

[oldbuffer]

1. Three years is fair going for an electric shower, particularly if you are in a hard water area. Surely out of guarantee?
2. Not the most expensive electric shower in the world, shall we say.
3. If the head and / or hose are allowed to clog up / become kinked, likely to lead to PRD failure.