Dizzy clamp spanner

[el torro]

I was told of an offset spanner for clamp nut that existed many years ago ,anyone ever seen it

[Mazzini]

1/4 drive ratchet, short extension (if required) and socket does the job.

[rgh0]

ratchet ring spanner - e.g. gear wrench with a pivoting head is suitable.
cheers
Rohan