Place your bets now! So I had this idea of putting an LED and rectifier in series with the multiplier in an ioniser to act both as a power and ionisation current indicator. The theory was that the current drawn by the multiplier would vary according to the work it was doing, and that would make the LED glow brighter. I decided to start by putting a meter in series with the ioniser section (without the existing power indicator) to see what current it drew.
It's low. Very low. My big industrial Fluke meter wouldn't go that low so I had to use a cheap hobby multimeter, and in turn that didn't actually have an AC current measurement option. So I stuck a rectifier in series with the incoming mains supply and put the meter across it so that it measured the AC current. Just in case anyone thinks that the lack of smooth DC would skew the result, I subsequently did it with a small capacitor across the meter to smooth the result and it was exactly the same.