After a long time of messing aroung I got it to work by tricking the software into thinking it was actually in the default location it likes at 'C:\Program Files\Adobe' by creating directory junctions. In order for it to work the hard drive must be formatted with the NTFS filesystem.
I used http://code.google.com/p/symlinker/ to create the directory junctions. You need to map the following folders to folders on the other hard drive you want to install the suite on. Run the symlinker software as an administrator.
- C:\Program Files\Adobe
- C:\Program Files\Common Files\Adobe
- C:\Program Files (x86)\Adobe
- C:\Program Files (x86)\Common Files\Adobe
Make sure that you select Directory Junction in the dropdown for type of link otherwise it won't work.
In the symlink program the box which says 'give a name to the link' is the folder name. So for example to set up the first path you would enter 'C:\Program Files' in the top box. Then 'Adobe' as the link name and then '[New Drive]:\Adobe From Link' (as an example) in the third box and then do the same for the other 3 and they all need to go to different folders.
Then when you've done this and checked that the folders are being mapped correctly you can simply install the adobe suite into C:\Program Files\Adobe (where it wants to go) and it will actually set itself up on your other hard drive.
I know it's not common to even think about putting it on another hard drive but I had to and I hope this will be useful if there's someone else out there that ever needs to and will save a lot of time!