Azure Fortigate Migration???

I have setup an Azure Fortigate in ARM for a customer and it works fine... but...

they had an old Classic vNet that contained some machines that needed to be migrated to ARM... what they have done is migrate the whole vNET and they now want to migrate the Fortigate into that vNet..

My thought is that it's easier to move the servers to the Fortigate vNet rather than attempt to move the FGT (with it's 8 IPSec VPNs) to the migrated classic vNet.

Thoughts?