socks - what are the best after we've grown out of Gap 4-5yo?

[NotAgainAndAgain]

On invaluable mumsnet advice I've got hooked on Gaps socks. White were great for school, all other colours - good for not doing rainbow outfits for weekends.
But now that DD has grown out of their sizing chart< I need to find a good equivalent. Any ideas?

Or should I admit I should finish with mumsnet since 5 is a mature age grin

We successfully 'progressed' from Gap socks to those sold in John Lewis. Only thing to watch for: no more rubber 'writing' on sole of socks, so dd slipped over a few times when on slippery floors in just her sock feet!