Ok guys, here's what I have done so far:
In terms of whether the video is switchable or not - it didn't say anything about it for that particular GPU,on the documetation on the nvidia website. There was a mention of later GPU's being switchable. I guess that mine isn't.
I followed the instructions for using rpmfusion to update the nvidia driver, but this failed to boot at all, although there is another boot option that does work.
I re-installed fedora 17 with KDE - it wasn't really necessary for the video problem, but I wanted to make sure I had a clean install. The Live CD failed, I had to goto troubleshoot to set a lower graphics mode, then it was fine. I installed all the software I wanted and installed all availble updates.
In terms of trying to alter the existing system, I thought it might be better to have another grub menu option entitled "Fedora 17 Test Nvidia", and alter files, settings etc for that, leaving the existing configuration alone.
There is a tutorial that I have been following:
To keep things simple, I have started with just making the new grub menu option with a different title, but it does exactly the same as the existing fedora 17 option.
The next steps would be to alter this new option by creating a new kernel and img (by copying the existing ones to a new name). Then alter these by whatever means is going to work.
I have found this as an alternative to using using rpmfusion.
This says that the instructions shouldn't be necessary because distributions are encouraged to package their own binaries to acheive the same thing - I take that is what the rpmfusion is.
Also, I have noticed the nvidia-config cmd which wasn't mentioned in the rpmfusion instructions. Maybe this is part of the problem?
Any that is is my plan for now, am interested to hear any thoughts.