Lost track of battery numbers, keep messing about with them. I bought a load of Trojan Batteries at Newark Autostumble, with a drum of acid, some years back, so use them. I believe these are unobtainum now.
Suspension. Looks like you have done the right thing by marking the serrated plate that holds these units in the adjusted place. They can be misaligned or full of rust/paint/crude and not grip. Thus the suspension drops.
If the adjuster is not slipping and the unit is drooping, or on the bump stop, it is dying or dead. Changing the unit is quite exciting. You will never push the unit out without destroying the whole arm. So its time to burn the rubber out. Once it has singed everything in sight and stunk the place out you can cut the steel container away from the stub axle, clean it up and prep for the new replacement. Except these now come from Germany where the tooling was sold by Russ after a refusal to cover the liability of manufacture by the British interests. Consequently the British price has risen and availability got patchy. Should you be able to buy some units they press fit into the arm. One chance to do it right.
New rubber transforms the car. But it is expensive now. You can drive on the bumpstops but it is an uncomfortable ride.