Leaking Shower of unidentified make and model

because there are so many shower valves on the market,and most have no identity marks on them,it is virtually impossible to source spares for them,you could contact a company called shower doctor on the internet,send them a picture they might be able to help,but it might be cheaper just to buy a new one and have it fitted,but keep the receipt for future reference in case you need spares in the future.

I agree with D & R, I personally use Shower Doctor, Shower Spares or Divapor if I think the cost of replacing a valve is cheaper than renewing. If it is an electric shower, 99% of the time I replace as it is cheaper than repairs and of course the labour & time to do. If the shower includes valves, it may be cheaper to try one of the spares websites as mentioned. They are very helpful.