the old Lucas handlebar switches have grey cables which run along the bars and into the main loom. the cables which will I'm sure be similar to triumphs and nortons but all with different internal wire colours etc etc
Nope, in '72 and for many years both before and after, Lucas
was the only electrical components supplier to the British motorcycle industry and, because the latter were collectively and equally as tight as the proverbial duck's rear orifice, they got exactly
the same components.
The only particular peculiarity with '72 is, about March, certainly Triumph and BSA changed one of the switch clusters:-
. before then, from the beginning of the '71 season, the cluster with indicators switch had been on the right 'bar and the cluster with the dipswitch had been on the left 'bar;
. after then, the cluster with indicators switch moved to the left 'bar and the cluster with the dipswitch moved to the right 'bar;
. while the indicators switch works the same on either 'bar, simply swapping the earlier dipswitch from left to right means it works the 'wrong' way - up-for-dip-down-for-main; so the dipswitch internals were changed to work 'correctly' on the right 'bar;
. if you need to go for a complete replacement, note the Sparx dipswitch cluster is the later one, there isn't a pattern of the earlier one.
supplier of just these cables, perhaps already made up ready for resoldering to the switch end, in original grey outer cover colours?
'Fraid I'm virtually certain there isn't one.
Or, if there is one to become better-known as a result of this thread, I suspect Andy Gregory would like to know too ...
That said, if you can solder, make your own with the widely-available correct individual cables in grey or silver heatshrink?