SMART repair or respray?

[Shaoxter]

I scratched the front wing of my M5 against the garage
No idea how it happened, it's a small garage but I've got in and out hundreds of times with no issues... luckily I stopped before I took the wing mirror off!

Anyway I'm wondering what a SMART repair would cost and if it's recommended? It's about a 12in/30cm scratch on the wheel arch, not very wide but it's pretty visible and I think most of the paint has come off. I've been quoted resprays for around £250-300.

Also does anyone have any recommendations around North London?

[7even]

You'd probably be a wee bit cheaper from a smart repairer, but the million dollar question is getting one that's good and reliable, perhaps the local section on this forum may be a better place for a shout?