^^ thanks again mate, I've filled out the forms & will be sending them off with a cd (I know right) of photos next week. Fitted base of rear seat back in tonight & the other race seat to check everything fits, looks good!
Untitled by Christian Taylor, on Flickr
In the meantime I've found a guy who will make me a custom steering wheel without core transfer, so I've designed one up I'd like and sent it through tonight. Better yet, it's made from an OEM wheel so it'll fit perfectly and take the standard airbag! I've ordered one similar to this, but with black alcantara on the top & bottom portions of the wheel & a grey center stripe.
22c348801f0a4a9398614724413cd749 by Christian Taylor, on Flickr
Here's my super-technical drawing:
E46 Wheel by Christian Taylor, on Flickr
Will see what it's like when it arrives and post results!