Thanks...
1. Yes the MAC address of the USG is static
2. Seems to work with a direct connection to a laptop
3. 2 versions ago ... I believe the version that shipped with my router was RUT2XX_R_00.01.12.3
4. Not sure what you mean here ?
I am also becoming aware that there are issues with the Failover/Failback functionality of the Ubiquity USG-3P, which apparently has been present for years ! I am not sure where the issues I am experiencing are coming from now, though something has changed with the Firmware update that has exasibated the issue ?
I am leaning towards DNS issues, suffice to say it's now driving me a bit mad....