MrCJ, an 1 1/4" ring spanner does the job well, if you dont have one ask at a local machinery shop like a tractor dealer for a lend of one, they can only say no, put the mower on it's side so you can grab hold of the base plate and push, an 1 1/4" ring spanner is a big spanner and provides plenty of leverage, if the rest of the mower is RS it does not really matter what means of stopping the retch from turning over, if it does not have the base plate, get inventive and rough if need be to the rest of the mower but gentle on the nut
I'm only a home mechanic but have both the right ringy and socket so I dont see why they should be hard to find someone with the right tools? CAT dealers or fitters also have big AF tools if you know of any.
