So I've finally got round to this one. I've found a few useful guides online. I'm stuck on how to pump it up however. It uses a football type needle adapter. The official guide I've found says it's a delicate operation and that you need to move the needle gently from side to side to avoid breaking valve. I can't figure out if you're meant to push the needle right through the rubber valve or if the valve has some kind of mechanism that means you don't need to do that.
No air seems to get through which makes me think I need to push the adapter right through, but if that's wrong I will have punctured the valve and I doubt I'll find a replacement.
The valve looks like a little ball from the underside (last photo) and when you push the needle into it you can see that it's slightly split (third photo) but seemingly not the whole way through.
Another consideration is that if you are meant to push the needle right through it looks as if no-one's ever pumped the forks up before.
The need goes in the little hole at the top (maybe that's obvious)
Pics in a second