welcome to the forum, Lewis.
are you a DIY kinda guy that likes to do things outside of the box ?
I made a collet wrench for a hand-held Dewalt out of a lawn mower blade quicker and
cheaper than I could buy one. all you need is an angle grinder and a metal cut-off blade.
(and of course a flat piece of steel)
or - if you can find the common thin 3/4" flat wrench, you can grind it out to fit.