Ross you would have been better sticking to the other thread click here
I didnt realise you where trying to dual boot from two drives.
Im not sure how this is done,though going this way i think you would need to change the bios boot order,basically booting from the Linux drive to get access.Going to be a pain as you would need to change the bios everytime you wanted to boot into windows.
There maybe a way around this by editing the boot menu within GRUB.
Some of the real experts may help further,lookout for
Octal / Lastchip / DieSse these guys know there way around Linux very well.
Ive only tried dual booting from one drive and on all occassions its worked fine...well except my first attempt.