Cheers Webmonkey. The scratches were a bit of a spur of the moment thing when I was painting the armour on the legs. I'd always intended the knight to look fairly 'clean', minus the obvious heavy oil shading, but the armour sections were looking like the needed breaking up a little. My plan with the scratches was just that it scratched the paintwork, not right through to the metal underneath, to prevent it looking too heavily weathered.
I might have gone a little overboard with them and you're certainly right, some of the larger ones could use a metallic streak down the middle. If the big guy doesn't sell on eBay I'll grab him back out and touch them up. Cheers for the advice!
EDIT: I just re-read that and I talk like I know what I'm doing; I really don't. I honestly do appreciate any advice from the painters here and I'll definitely act on it if I get the chance. I don't want to come across like I think I know better.