Help to identify mystery clicking sound

[CCS]

All wrong!!!
(and no, it definitely is NOT my knees - though there is a weird clicking noise sometimes from somewhere in one of my legs when I run...)
Anyway, after much scratching of heads and riding round the block at the LBS (the noise only appeared when riding - not on the workstand), the noise is apparently down to the little lug thingys on the chainring that help to change gears being a bit worn and loose... nothing to worry too much about - they said not worth changing the chainring yet, unless the noise was really annoying me... so if you hear something rattling its way through the Surrey Hills over the winter, it is probably just me & Champ.

As an aside, when I took the turbo wheel off the TT to go for a ride this morning (later abandoned due to rain), its rear wheel was also making a really weird noise - managed to diagnose & fix that one myself - loose cassette. Now, I can speed stealthily around the roads of Hampton and Sunbury tomorrow...
One day, perhaps I may get vaguely competent at maintenance?