Problem solved. The grub stanza needed adjusting :
title MsDos 6.1
map (hd1,0) (hd0,0)
map (hd0,0) (hd1,0)
With regards to how it got there. I had an old 486 SX33 rotting away. The cmos battery had run out and it was not the replaceable type but the variety that are soldered onto the motherboard. So I took out the HD and put it onto an old pc running RH7.1 to see if it would still be operational.
Congratulations to Grub !!!!
Makes you laugh at how restricted Dos is/was in comparison to Unix/Linux.