Jeff I have a couple of speedo drives with the correct rotation. They came from post war Flying Fleas, so they just need the axle hole bored out bigger. They are £45 each plus post if you are anyone else wants one. Email me for a picture.
No Jesse, the WD/C speedo drive is the normal, through the brake plate item like this. The M20 speedo drive is totally different
I have got one like you need, but I think it is the wrong rotation for a left hand brake plate. I'll check it tomorrow. Ron