She just started this a couple of days ago, but we haven't really been able to get any food into her since then (she is drinking milk fine and as you can imagine more than usual).

My plan is next meal to not say anything (e.g. not acknowledge the raspberries at all) but just keep shoveling food in (oh an do it out on the balcony wearing old clothes!). Surely she will give up and get bored and start swallowing rather than spraying it all over the place?

Anyone else had this problem / found a solution?

my 7 month old does this a lot too, he still eats though., i went to a weaning class a few months ago and the health visitor that done then class said that if your baby does ths when she's beng fed, it usually means they're not hungry. Thats how i usually know when my son has had enough.
As for the not being able to get food into her, something my health visitor told me, when i was struggling with getting my son to eat, was that no baby will ever starve themself! just keep at it, when she's hungry, she will eat!