Finally the rod clevis for the end of the skeleton raising cylinder arrived today:
Here it is attached to the cylinder complete with foot clevis at the RHS and plates to mount to the lifting bar at the LHS.
Here is a highly technical plan of what I'm trying to do.
After a test run my rig failed to lift anything, then almost destroyed itself as I increased the pressure. Due to the short distance between the hinge and the piston attach point then once it got going the unhinged end of the lift bar went too fast.
I am going to have to maximise the angle between the cylinder and the base plate as the piston attaches to the bar quite low so a large force is required to make it move. Maximising this angle helps to reduce the force required to get it started.