Cat II/III approval is usually an issue for the operator - in that they are required to demonstrate adequate crew training and aircraft capability etc. before the CAA with authorise the airline. As a result minima are usually found in the airlines operations manuals, since they depend on a few variables as well as the usual regulatory minima.
Example, the B737 can perform Cat 3A approaches and autolands with either landing flap 30 or 40. If 30 is used, the minimum RVR is 250m, using F40 minimum is 200m (due to improved view over the nose with F40).
There are many other factors which determine the approach capability of an airfield (and aeroplane), such as approach/runway lighting, availibility of backup approach aids etc etc. That's why the minima published on plates are fairly generic, and at best usually only for Cat II.
Our company doesn't use plate-published minima anyway, like many others, we are required to refer to our Aerodrome Operating Minima manual, part of the overall aircraft ops manuals.
OCH - Obstacle clearance height - the minium height to clear all obstacles around an airfield within a defined radius (can't remember what it is, but it increases in size with the approach speed category of the aircraft).
OCA - Obstacle clearance altitude, ie the same thing as OCH but measured from sea level rather than airfield elevation.
(D'oh - TB beat me to that last bit!)