Seized 90 drivetrain

Hi. Drove my fender 90 on Saturday without problem, but when I went to drive it on Monday, engaged 1st ok, but on lifting the clutch, the vehicle wanted to move forwards but somewhere in the drive train it’s seized. To the point when she stalled. I struggle to believe that a brake has seized to that extent - the handbrake has never been that tight so I’m at a loss to think where I should start my investigations. Any thoughts gratefully received.

Park on the level with handbrake off and go underneath and see if you can move the handbrake drum at all, should rock back and forth with the play in the diffs / gearbox.
Mine used to seize up with rust and other crud collected in the drum.

As suggested above, it sounds just like a seized handbrake.

Try going backwards. May release the hand brake if ceased.
If not do as per 2nd post

Could be seized master cyl as well as above answers. Get it up on the jacks and see what moves.

Behind the HB drum you will see the linkage to the actuator, tap it into the back of the drum with a hammer, this will release the brake, bit of common sense though, flat ground etc etc, its will still need stripping down, cleaning and some grease, perhaps even new shoes.