What I have now done is pulled all the gust out of my old corded drill, so all that remains are the stator, gearbox and chuck and casing.
I then screwed the drill case to a few bits of mdf to get the old drill chuck to the same height as the mill driveshaft.
Attached the chuck (old drill) to the mill, then drive the end of the stator with my new drill. the new drill does not raise a sweat at all and a very slow crush speed (as the new drill is effectively driving a 10:1 gearbox)
In low range, the new drill rpm is 1000 no load, so I crush at 100rpm, there is hardly any husk damage.
Not the neatest solution - actually very ugly, but oh, so effective. and will do until late august!
Would show pics, but a bit embarrassing atm, will clean it up and post pics!