Hi,
I've got a shower/bath mixer tap that's leaking and has been getting worse over the last 6 months or so.
Could someone please help me out with a couple of Q's before I attempt to fix it. I live in a block of flats and turning the water off involves turning the whole blocks supply off... so I want to get all my materials together before I start the job.
Here's the tap:

It's the top level that controls the bath or shower on/off that's the problem I think.
1. What kind of seating can I expect to find in there? i.e ceramic or plastic?
2. What kind of washers I am likely to need? O-ring ones...?
3. If I end up having to replace the whole valve seating (it leaks quite badly now) what sort of price am I looking at?
Any help and tips would be greatly appreciated thanks!