Yay ! SUCCESS !!!!!!!!!!!!!!!!!!!!!!
I fired up the venerable old PC today and looked again at the BIOS. There was no data at all for the hard drive configuration.
There was an autodetect function, (autotype) which I selected. It looked at the HDD and put the correct configuration in:
I then rebooted the PC, and HEY PRESTO !!!!!!!!!!!
Everything is back. All my Psion back-up, my old files and accounts info, everything.
That was so easy, and the so-called "expert" I took it to was an idiot.
Thank you all so much for your help. I think it was Saab Dastard who first suggested the autodetect - called autotype on my PC to reset the settings the DOS was using to read the HDD.
If any of you are ever holidaying in the South West UK, please pm me and I will buy the drinks !
Many thanks to all again.
My next job is to back up this HDD since it is quite elderly.