If anyone is interested the following NOS Honda parts are for sale...
UK spec low handlebars for CB750 K1 and K2, part number 53100-300-610 - £85 + post
UK spec low handlebar cable set for CB750 K1 and K2 comprising three cables as follows:-
Throttle cable part numbers 17910-341-611 and 17920-341-611
Clutch cable part number 22870-341-610
£55 + post
All are NOS genuine Honda parts, in their original packaging and have been stored in the house for the last 30 years. I have finally completed my planned (since 1985!) restoration of a US market 750 K2 with high bars fitted hence these UK market parts are now surplus.
Pictures can be sent to anyone interested.