Thus there is bugger all I can do about it to fix it!
Not true, there are many different ways around this and I've already mentioned a few.
A final question. How do I change the partition size then inside the VM?
Generally speaking resizing a virtual partition on a virtual disk is no different then resizing a physical partition on a physical disk so act accordingly. That said, I do make use of GParted Live both from CD and ISO Image depending on whether it a physical or virtual machine. Although using it on a Windows Virtual Machine under VMware Fusion requires some tweaking of the settings and the easiest is to temporarily remove the USB Controller before booting the ISO Image. This resolves mouse tracking issues that would require more advanced tweaks. Otherwise use Windows based utilities.