Hi, thanks for all your replies! I'm in the middle of organising a housemove and haven't been on here since I began this thread - sorry!

It's definitely, definitely not artificial colours/preservatives - I'm really careful about how we eat, so it's organic wholefoods and homemade all the way. I don't plan on introducing processed foods for quite some time yet, if at all. But I know that can be a problem with older children, can't it? My mother swears I used to go ballistic after anything red when I was young.

I really appreciate the suggestions about keeping calm whilst redirecting her to other activities...I actually think the whole reason it's stuck is because, stupidly, the first time it happened my husband and I completely freaked out over it. Which, of course, Miss A thought was hilarious. Sigh. Really, we probably made this a lot worse than it is. We're definitely trying to react in a very even-handed way when it does happen...she actually stopped for a while and then started up again yesterday, and incidentally we also realised she has been teething again. God. I hope this isn't her chosen form of pain-relief. Anyway. Thank you! Hopefully we can try to put an end to it.