Fork top nuts T3

Was having difficulty tightening the 31mm A/F nuts at the top end of my forks.
Success! I have found that a common or garden plumbers box spanner used for the backing nuts on sink and bath taps fits perfectly; clearing the wiring harnesses, clutch cable, brake pipes etc that get in the way. And all for £8-50!!!
All the best,
David.

Which bike model etc.?

Triumph Bathtub?

As if Gerry!!!
850-T3 California.
All the best,
David.