Hi,
I have an almost bare chassis and am going to change most if not all bushes in the rear susp. Also going to paint it al.
Will it be possible to remove the spring plate with no body, gbox or motor as weight?
I have the spring plate cover off and the bush there is distorted.
I have no idea what the rear sag was like when I got the car because it was half stripped so it may already be a bit lowered because of age.
Thanks.

Bolt the spring plate cover back on loosely with at least the 2 rear-most bolts (to stop the arm flying into your head).
Place a trolley jack under the end of the arm.
Bolt a heavy chain securely under and thru the bottom of the trolley jack, in such a way that it can't slip around or move under the jack.
Bolt both chain ends thru the upper shock absorber mount hole on the chassis.
Jack the arm up, carefully. The chain will keep the chassis from going up with it.
Using a hefty pry bar, slowly slide the arm outwards away from the torsion housing, just a little bit, until it overlaps the end of the torsion housing plate.
Slowly let down the jack, and the arm is now free of tension and out of the torsion housing.

Undo the chain, move it around to the other side and do it all again. Make sure you also roll it over your foot, slam it into the side of your ankle, and swear loudly just as your wife is greeting friends at the front door.

Excellent advice.
Not sure I can do the first part though!

So, mark and remove the pivot arm first. Tension with jack and chain, then knock the spring plate away from the stop.
I need to grab a 17mm hex socket. Is shorter better for access to the pivot arm and gearbox drain and fill sockets? Bunnings have a 78mm long one and stupid cheap has a full set that look like normal socket size.
Thanks.

I used a normal 1/2"DR hex, it's about 2" long all up.
They bolts have a heap of torque (80ft/lbs I think?) so a cheap socket won't cut it, mine is ABW.
There should also be a notch on the outside tube around the bolt that has been peened into the bolt head, if that is not bent back out before unbolting then the torque loading will be much higher again.

All good matey. All out. 7 different places before I found the 17mm hex. Passenger bolt thread flattened but d/s like new.
Not much noise when the spring plate let go. I've marked up where the top of the spring plate rested. Am I correct in assuming the I can take out the torsion bar and clean everything up and I just have to line up my mark when putting it back together?
And If I want to lower by a small amount I have to raise the spring plate slightly above my mark using the outer splines, and a mix of both splines for finer adjustment?
New bushes and bolt to come.

That's it, except for if you make the marks with a little tap of a sharp chisel, rather than a paintpen, then when you paint it you will still have your alignment marks on it and won't have to start from scratch again........
ahem.