You're welcome 🙂 that's a hard one as they seem a very rare wheel. To buy a new one costs $230 in the US and seen used sets going for $400. So I'd suspect £200-400 depending on condition abd tyres that go with them. This is just a guess mind.
Lovely golf btw, my mum had a mk4 in black gttdi she got new and still has it. What spec is yours?