Over the weekend my new power supply arrived - Excellent value and recommended - Nokia 5V 1200mA - £3.99 delivered from Amazon
My final SD Card purchase for now also arrived (Class 6 Transcend 8Gb).
I therefore put it all together with the existing approved USB keyboard (Dell SK115)
I also tested the SDCard socket using a cut down SD micro card adaptor which I butchered to expose the contacts so I could do continuity tests on the data and power contacts plus the lock/unlock contacts and the 'card fully inserted' contacts - All absolutely solid continuity with no problems or shorts.
The test points on the board gave a well within spec 4.9 V with everything plugged in and running.
So - Rpi verified USB keyboard, Standard USB mouse, Rpi recommended Class 6 8Gb Transcend SD card with fresh Debian image, power within limits with adequate current reserves, connected to Panasonic display via hdmi - result = Kernel panic - not syncing.
Repeated test with four different USB keyboards all drawing less than 100mA - 1 x Microsoft, 1 x Logitek, 1 x HP, with a fresh SDCard image on the Transcend each time.
Just for completeness, I removed the network connection and all the USB devices, and tried booting with the minimum load as reported by others - same result.
I believe I've gone as far as I can with this example so propose to return it for a replacement to RS.
If anyone has any good ideas before tomorrow morning, I'm happy to try them, I'm certainly not short of SDCards, power supplies and USB keyboards!!!
The 'Things bought to try and get the pi working' bill, now comfortably exceeds the cost of the pi, but as they say, nothing ventured - nothing gained, and I'm far from despondent.
I will get a pi running sooner of later, and once I get one working, looking on the bright side, I'll have a load of alternative SDCards and keyboards to test verify, and report back on, so we'll find out which bits may have contributed to the ongoing reluctance to fire up the pi . . .