Ok instead of making a separate thread, i just post the simple mod here.
I used the original bracket that comes with the Skywatcher sw electric focuser and just bend it so it fitted.
Only had to use one screw 1.5X longer than the original screw to hold it and used a 6mm to 4mm coupler from Jaycar and only had to drill out the 4mm hole a tiny bit so it fits the focuser shaft.
I made a flat on the focuser shaft so it had a nice grip.
Now i can tighten the focuser and it will push the whole assembly straight upwards.
Once focused the knob on the other end will not turn at all so it is very rigid.
For people who want to secure the motor even better, you can fit a second screw on the other side 1.5X longer than the original.
See photo of a wee bit rusty bracket (better paint it
).