Just because I couldn't for the life of me find anyone who had the same BCCode in the same circumstances from a BSoD I thought I should put my fix up here, just incase I can stop some other poor sod going through the things I did.
Dell Poweredge T610
Dual 6 core Xeon 5650 2.66GHz
Win 2008 R2 enterprise 64bit (fully patched)
When starting (or restarting) a VM in Hyper-V the host system BSoDs with the following:
Additionally, VMs that do start never get beyond the "Hyper-V" splash screen
Chipset driver 5520/5500 was on version: 9.1.0.x - upgraded to 188.8.131.526 (latest)
This had to be d/l'ed from Dell as Windows Update did not have latest version.