I'm happy to say it worked! The USB CDD didn't do it's job though so I had to half-inch an internal SATA one from the same friend who loaned me the external HDD for my backup! Worked ok once I had that sorted but I had real trouble with my USB keyboard which prevented me from 'pressing any key' to boot from the Windows CD
In the end I had to enable a few additional USB device settings in BIOS but I don't understand why as the keyboard worked fine in the boot/post/bios screens and such. Just ceased functioning once the boot went further...
I've now got Windows 7 running and all my new hardware is running perfectly. It's a lot quieter although my case fan is spinning obsurdly fast compared to the CPU one. The CPU fan is automatically variable (or whatever the correct term is) so I wonder if I can replace the case fan with a similar one? I'll be building a new case soon anyway as I said but I'm still going to need a few extra fans when I do that I think!
The 212 DOES fit in my case and has a little space too, the side is still off anyway though as the borrowed CDD is connected but not installed. Will put the side on when it gets disconnected. The trouble with that is that my external CDD (a very cheap one) doesn't seem to recognise all cds, so I could have trouble once I disconnect the SATA one. It came with no paperwork and a CD with a few USB drivers and NERO burning ROM on it but I don't know if I need them for it to recognise other CD's. (It does recognise the driver cd thankfully so I can always do it later once I've experimented a little!)
CPU and system temperature are good though of course I haven't had anything more intensive than Chrome running so far. Will report on that later as I learn more performance wise. BIOS has recognised all 16GB of RAM so if anyone in the future happens to ask if Vengeance is compatible with Gigabyte's Z68 boards we can tell them yes!
The only issue I've had so far is that I was never given the option to reformat my HDD before the OS installed. The first screen after booting from the Win7 cd asks if you want a normal 'upgrade' from an older OS to 7 or a 'custom' installation which it notes will allow you to start from scratch. Or at least that's how it read to me...
Either way I never got an option to reformat and I would like to start from nothing so if anyone can tell me how to go about it without using a slave HDD I'd really appreciate it.
Right now I'm going to switch off to disconnect this CDD and connect my peripherals! Then it's time to see if I can spot any nice differences in my games. Remember it's still the old Graphics card but I'm sure that extra power will do SOME good at least! Will upgrade to DX11 while I think about it as well as it's one of the main reasons I upgraded to 7!
Cheers for all the help and advice guys, it's all looking spot on so far!