So, finally solved (well worked around this issue)

After a lot of back and forth to MS, we agreed to apply the on demand hotfix 3033860 for SQL 2008 R2 SP3 and then turn on trace flag 3057.

The moral of this story being... be very aware of what is taking place in your environment, not just for SQL Server. This is something I try to do on a daily basis, but in this instance I had no sight or awareness of the hypervisor move. Hopefully you will be a little better placed now if this ever happens to you. Although, come mid 2019, non of us will be running SQL 2008 R2 right? 😉