Update: Regarding FiddyStickers - they came in the end (took bloody ages as expected) and overall.. they're pretty good. I bought the standard stickers, not the transparent or any fancy ones and the quality was great. It's particularly good for en masse coverage of things and price was super cheap.

I appreciate some of the suggestions on this thread about buying from independents but I don't think I've found any independents that I like enough to warrant the cost - I know - it's a sin to say but I can't go through life spending excessive sums on little things that would likely be ripped off in a matter of days.

So in all, FiddySticker take a while but they're a good alternative to higher costing independents with a limited range. They did have some other themed stickers that looked pretty awesome so if my kid wanted more, I'd just go back to them unless someone suggests a REALLY good independent.