Can't shrink VM disk space in Fusion 6

Trying to shrink a VM containing Windows 8.1 Enterprise on OS X Mavericks (10.9.1) and Fusion 6.04 on a MacBook Air mid-2013 have followed these instructions:

• Shrinking Virtual Disks

So I've essentially defragged the SSD (which I've since learnt isn't ideal) and then tried shrinking the VM in Fusion hard drive settings for that image - it appears larger in the settings than it really is (233GB vs 116GB). The disk size controller won't budge to the left.

The VM was originally generated by Fusion 6 from a Bootcamp partition.