Yes, compressor kicks in when the A/C button is pressed to ON & I pop the engine hatch to check I can see the pulley spinning, so it's definitely running.
I had the system filled last month with RS24, a replacement for R12, as the system was never modified for R134a & there's no signs of leakage.
I am going to speak to the company who charged the system, to see if they can check the pressures while the compressor is running, next week.