Okay. I will try that, but in the meantime I've found something else that might be a culprit. I stopped and thought - maybe it's the albums that I'm playing at the time and it dawned on me that the clicking seems to be happening on certain albums more recently imported and analysed under MC28 rather than older ones imported and analysed while I was still using MC25.
I have Volume levelling on because it works so well. So using dBpoweramp I looked at the tags in a few recent albums and noticed that MC hadn't written any of the analysis tags to them, whilst other recent albums had those as well as waveform analysis tags written that I don't want, so I deleted those waveform tags.
Maybe the clicks are a sudden change in gain caused by a Volume levelling glitch on these albums. I checked using Analyse Audio on the files without MC tags and they had already been done, but I re-ran Analysis again anyway and checked using dBpoweramp that the tags were written.
I'll play these later today and see how it goes. Will also try what you suggested. I leave it a week before reporting back just to be sure and not have you chasing my tail.