The current thinking is that seven is installed on a small logical partition to separate it from the frequently changing mountain of media data (recorded tv, movies music etc) on the rest of the same drive.
The idea was to have that partition as the os in perpetuity & thus free up something like 950gb across that & the other drive for media.
From my own reading, it seems that won't be easy to do, with the possible exception of booting from the ms dvd & using it to format drives as required, then bailing out of the install once formatting is complete.
Since I enjoy this kind of mucking around with pc's (geek), I might just do that. Thanks for the advice.