Well, I went to have a look at it and after wasting 15 minutes looking in the wrong places for the fuse box, I eventually found it and checked the fuses which were okay. Of course I managed to kill the radio so finding the radio code was another job to add to the list. ;-)
I then turned to disassembling the instrument console which turned out to be really easy. I did the usual wiggling and unplugging/replugging of all connectors but nothing came back to life so I removed the instrument pack prior to sending it off.
Seeing as I had my torx screwdriver in my hand, I thought I'd have a peak inside the console but there wasn't really anything that I could easily get at without pulling the needles off the dials which I didn't want to do without being sure if that was the way forward. I put the back cover back on and tried it one last time reconnected to all the wires, and it worked!
I've no idea what made the difference or how long it will go on working but for the moment Arnold Clarke isn't getting a bucket load of my mother's money whcih makes me happy. ;-)
I've suggested that it might not be a bad time to think about changing her car for something more reliable & less costly to repair.
Tim