Squealing springs

Probably obvious to many of you, but on our return from the CMCC site at Cheddar our rear suspension increasingly sounded like something terminal was about to happen. Nothing appeared loose or broken so had a good look underneath when we got home. Nothing untoward to be seen, wondered if the spring assistors were past their best and allowing the springs to be overloaded, or maybe the springs had settled allowing the shocks to bottom out. Decided to jack the van up to unload the springs, then using a tyre lever to slightly separate the spring at each end and liberally grease where they normally contact.
Hey presto, now no noise at all. Wish all problems could be that simple to fix.