Thanks Rich and Dave,
I don't believe it is leaking, the fluid level has not changed much, but it gets discoloured in about a year and a half, which means the rubber parts inside the cylinders are deterioriating.
I'm also noticing that the clutch pedal needs to be pressed down farther before it begins to disengage (like the piston is not returning all the way back). The transmission is also getting more dificult to shift, especially into reverse (no syncro).
I've had similar problems with other cars.
I might just take it apart today, clean / polish it and see what happens.
The prices shown certainly are lower than local jobbers here!
I'll post my results - or ask someone for a ride to the dealer