Thanks for the reply. That was what I thought; you could "make" it fit.
Might make my own - got the rails here as they came with the case and left over wood from desk so all I really need is to make a box structure.
The case is awesome - I have 7 hard drives and a dvd drive in it. It is very deep which is the only thing. Superbly made and I managed to get when Coolermaster UK had a clearout of old stock on an auction site. Had almost bought it full price a month or so previously. My only gripe is no reset switch, only a power switch is present. I can take photos if you want, but would have to give me a day or so.