kiwifidget:
If VF ring me while Router1 (not me) is receiving calls can they trace the IP address that the call is going to thus identifying the location of the offending router?
Yes,They should also have a list of IP addresses that have registered against your account on their server, so should be able to look at that at any time.
kiwifidget:
They can then log into it and remove the SIP setting?
Yes
kiwifidget:
When Router1 is receiving my calls, will its VOIP light be on?
Not sure on that exact model of router.