OK I screwed something up
I'm sure there's a fairly easy solution to this so how do I fix it?
Here what I did. I had Ubuntu 13.04 installed on SDA1 and Xubuntu installed on SDA2. I used Gparted and deleted Xubuntu/SDA2 and expected that I'd need to update grub once I booted back up.
But..... It won't boot and tells me its "unable to find partition" I thought the boot loader from Ubuntu SDA1 was in control but obviously that got overidden by the installation of Xubuntu on SDA2 so the boot loader is confused. So how do I fix this, i.e remove the SDA2 bootloader so I'm back to just SDA1 again?