Found a drip through a downstairs ceiling this morning and it turns out that the thermostatic control on the shower is leaking. Better or worse, depending on how it's waggled but I guess that means I need to change or service it. (For the moment I've built a dam of silicone to ensure the water flows into the bath instead of over the edge like it was). The bathroom will be done, eventually, and the whole thing will be swapped, so there's little point in buying a completely new set up.
The question, how do I identify it to source a new one? The flow and temp controls are two concentric chrome disks with levers projecting. When you unscrew a lever, there's a thread with an allen key hole in the end. I can't see any markings anywhere on the outside (I'm a bit reluctant to take it apart on a Sunday). Judging from other 'features' of the house installed before my tenure, it's bound to be a cheapo....
Is it a matter of taking the cartridge down to the PM and getting them to ID it, or is there another way?