I have the same issue with my anthracite coloured VW Motorsport alloys - I haven’t kerbed any of them, but there are one or two stone chips that they’ve picked up I’d like to sort out and VW can’t tell me what colour my VW wheels are!
Have you tried your local Halfords branch? - either take your car in if you’ve got a Halfords superstore nearby or take a picture of your wheels and see if you can get a red touch up pencil kit that’s a close match (it won’t necessarily be a VW paint colour). That’s what I’ll be doing to get an anthracite grey touch up pencil that’s a close match.