Right, that's my question answered. I was under the impression that modern cassettes, regardless of speed we're of all the same spacing and simply used spacers to compensate.
The whole point of wanting to chuck a bodged 9 speed is that I have the rest of the drivetrain in it's entirety minus a cassette and fancied playing around with a close ratio cassette. Alas I'll have to throw an extra £20 to get exactly what I need (:

I did double check and no spacers on the hub I missed, so defo a 'native' 8 speed cassette.

Cheers all and sorry for confusion.