Min Sink
Mine certainly has Class A on it - I've just fired it up again, and sure enough, the London TMA and Channel Islands zones are all still there!
As I mentioned before, what it doesn't have is MATZ stubs or any indication of the ATZ within a MATZ.
Crossedcontrols
I can't comment on the flux gate compass. What does one of those look like
My guess is that the turn co-ordinator works by looking at the rate of change of direction and the aircraft speed and computing what bank angle would be required to produce that rate of turn. I can't see how it would be able to work with airspeed, only groundspeed, so its accuracy must be limited. In extremis though, it would be a lot better than nothing.