i have not got a clue how to remove the disc, what am i missing?

you have to remove the hub and press the bearings out to remove the disc plus you can damged the bearings doing it

i thought they were bolted on

hrough the front of the disc you have 13mm bolts to undo the disc dont undo these until last you also have some holes in the holes 45 torx bolts x5 or 6 undo the driveshaft nut then wack the poo out of the disc or buy the tool that bolts in the back to push out the bearing
Laser 4288 Brake Disc Removal Tool Ford Transit | eBay

After the last few pair of discs I fitted I've decided that in future I will budget for new bearings, hubs and discs as it's likely to be cheaper in the long run . They were all done using the laser tool as well

I agree with the above regarding the bearing, if the bearing has never been replaced before or it's been in a while & wasn't fitted with a smear of copper grease around the bore that locates it in the upright then getting it out intact will be lucky. If it's seized in badly getting it out at all will be a fight! When it all goes as it should it's not bad to do but as with most things in life...
I think the RWD is the same with a stub shaft in place of the driveshaft to keep it all together.

There's a pdf of how to do it with the Laser tool, makes it sound simple