Morris Minor Owners Club

I am currently trying to rebuild a 1275 Midget gearbox. I have previously successfully rebuilt several 1098's and a few 948's. The 3rd motion shaft, however, is of different construction to the Minor boxes. I am stuck with the remaining parts as shown in the photo - which don't want to budge. I am coming to the conclusion that the disc between the 2nd and 3rd speed is fixed to the shaft. Is this right. Also, are there any other spring loaded plungers holding the gears on (I'm thinking probably 'yes').
With the Minor gearbox, the last thing to come off is the bearing with the use of a hollow drift. With this one, however, it looks like you have to take off the bearing so you can get to the spring pins to remove the 3rd speed gear? I tried some heat but couldn't shift the bearing.
Sorry if this has been covered before, but I couldn't find anything. Any advice would be appreciated.

The bearing with the circling should pull off, and so should the splined centre. There is a baulk ring between it and the cogwheel. The disc is fixed.

The attached file is an extract from the BMC Parts List for the 1275 gearbox, showing the components of the various shafts. Item 26 is the gear on your 3rd motion shaft, and item 32 is the 1st/2nd speed synchroniser assembly (the splined hub in your picture is part of this assembly).

OK thanks to both for that info, I'll have another go at the weekend