I’ve added the iwi kernel module from http://damien.bergamini.free.fr/ipw/ and it’s now finding the card and I can initialise it, but it doesn’t quite yet connect to the network. More checking needed I think.
While playing I decided to try the Fn + F5 buttons and was surprised to see a note about some new hardware and the Bluetooth LED come on. Pressing the keys again switched it off. I’m guessing the hardware was in fact the bluetooth adapter and despite the fact that the kernel was built with bluetooth support it wasn’t recognised. More investigation needed!