Thank you so much for your reply!
This is very helpful, I don’t do a lot of miles so might be able to get away with just letting them change at annual service if I keep an eye on it - even if of course I can’t check the level before journeys because of the slope.
I have already discounted a couple that look saggy at the back, the one I am thinking of is ostensibly in very good condition. Window motors, underside rust, sway bars, inside oil filler cap etc are all on my long list of things to check but I will add the struts and pay close attention to the arches.
Thanks again!