Fixing this required the removal of the code that attempted to detect virtual interfaces. Not wanting to remove functionality, but not able to keep the code in place, I implemented a work around solution (see 4 below).
Whilst in the area, I also fixed a few minor bugs i encountered (1, 5, 6 below) and stopped SSDP messages from going out on non-LAN interfaces (3)
All these changes are related.
Changes
1 IsInPrivateAddressSpace - improved subnet code checking
2 interfaces with no gateway were being excluded from SSDP blasts
3 filtered SSDP blasts from not LAN addresses as defined on the network page.
4 removed #986 mod - as this was part of the issue of #2986. Interfaces can be excluded from the LAN by putting the LAN address in brackets. eg. [10.1.1.1] will exclude an interface with ip address 10.1.1.1 from SSDP
5 fixed a problem where an invalid LAN address causing the SSDP to crash
6 corrected local link filter (FilterIPAddress) to filter on 169.254. addresses