Hi, much appreciated advice.Beauty of a bike!
It is hard to say for sure but when I try to zoom in on the gears it looks like some of the teeth are worn. A few look like they are a bit “shark tooth” looking. Maybe new chain rings and cassette.
I’m going to say ebay. Look for group sets. Maybe level up to XT. Or post a want to buy ad here. There has to be a few parts hoarders that visit the site. Shipping from the States would be spendy. But maybe someone from your side of the pond might have some parts stashed.
Another possibility that might be a bit blasphemous is buy a whole bike and strip it for parts. I’ve done it recently. Bought a whole bike with Deore XT bits for $40(USD).
Good luck. And do stay in touch. I’ll keep an eye out for stuff local to me.
Cheers