Pull off the temperture knob. Remove the circlip behind and the take off the Flow Knob. You'll need a hexagon wrench or large spanner to remove the cover plate. Obviously ensure the water is isolated before you do this ! The internals will then pull out. If you need assistance Mira do a fixed price service including parts. Ring them on 0844 5715000 for a quote.
Bob The Builder
February 2011