Stupid more like...you know what it is like...that feeling of just getting one thing done. I only popped in to workshop to glue the bit that I broke the day before, with plans to go and do something else...but it jsut sort of snowballed.. No food all day just two coffees, and I coudl feel myself getting more and more irrate as the day went on and blood sugar levels started to drop.
If I had not been such a muppet and pressed the casing in half, then I would not have had to fix it...Well it had to come apart anyway, to fix the magnets,
This is more for anyone else and future reference if they need to take one apart.
I pressed from the top, guessing that the there must be a bearing inside and that it would all press out in one with the shaft and rotor...WRONG
The casing cracked and only then was the construction method visible.
What one would need to do is first is drill the top of the rotor in two or three places, tap the holes and then use a puller to remove the rotor from the shaft. Maybe you could drive the shaft/sun gear out first from the rotor side. This may then give access through the bearing to somehow push the rotor out against the magnetic forces, but I am not sure you would do it.
Another possibility is to see if the pins that support the planets can be pulled out from the 'gearbox' side, which would allow pressing of the rotor out from that side with three pins. But I am guessing those posts are just a press fit in the casing and not going to be that easy to get out from that side