I managed to boot from a live cd and from there chrooted into the affected partition and found the problem lay with my system needing to be updated, which I did and it now works perfectly. I've changed the status to 'Fix Released'. feel free to change that if it's in appropriate.
** Changed in: update-manager (upstream) Status: Needs Info => Fix Released -- Ubuntu won't boot after upgrading to Feisty using update-manager https://launchpad.net/bugs/95757 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs