So the VM technician called this morning (Sat 23 Feb) and after running some tests he replaced my SH3 router, although he did say it was strange that the ethernet activity lights on the faulty router were flickering. With the replacement router up and running everything, including the ethernet ports. now work as they should. I would recommend that VM change their Customer Service script to flag that a router replacement is necessary if the power-off and pin hole reset don't fix a dead ethernet port fault. It would save everyone a lot of time.
Hi martinglake. If you have done a power off reset and a pinhole reset and still have wifi access to the internet but no hard wire ethernet connections you have a duff SH3. If Virgin CS try to send you to the Gadget team insist on a Router swop. Good luck!