Is it not my day, or am I just shit with virtualization?
After converting the vdi to a vmdk, the VMware VM a) has the vmdk stuck at 2.5Gb and full instead of 10Gb, and b) does not boot. Grrraaaaaaaaaagh!
I am reinstalling the OS onto a new mdk from scratch instead, I only had XP, uVNC, and ACT! on there, I can reinstall quicker than it will be faffing around with vmware-vdiskmanager and the like.