T25 iscorrect fitting.

Well I tried squirting some WD40 in the end and leaving it to soak, overnight. Nothing...

I tried heating it up with a blast from my Dremmel heat gun.

No luck. - Not given up yet. Perhaps I need to get them really toasty. Willing to risk it now as nothing to lose.

What I have found is that the motors are almost certainly the model between these I found Gimson Robotics

They have the 9T pinion on the shaft. Which slides off nice and easy if not needed.

2 screws on the plastic face plate, all have some wear and tear, pretty cheap screws and over tightened. One I had to release by loosening the other side and then forcing the plastic plate up.