Info on 230s Fintail

I've been offered the chance to buy a 230s Fintail. I'm not really experienced with Mercedes although I do own some other german cars. I've done a quick google but I'm having trouble putting a price on this. Can you give me an idea of price ranges? What are the common problems on these cars? I'm based in the UK.

I've included some text from the seller.

It's amanual 230S with relatively minor rust, new exhaust and tyres and an amazing interior, it was stored from nineteen eighty five until a couple of years back when the chap I bought it from picked it up from an estate sale, he got it going fitted a genuine merc exhaust system and some new tyres

the rear suspension is somewhat saggy with I suspect is due to a gas spring/shock mounted above the rear swing axle, its called a hydromat and a rebuilt one costs eight hundred and fifty euro's from classic Mercedes, you can buy a kit to replace it with a spring which is what the slightly earlier cars had anyway and costs about one hundred and fifty euro's so guess which rpute I will be going..... I have got some carb kits and a fuel pump coming from the states

the doors and rear arches are very good although the right hand rear door is rather speckled with surface rust, the worst affected area is the right hand sill, the sill itself could be repaired or new sills are available, the left sill looks fine it runs and moves around under its own steam but I am rebuilding the carbs etc, the mid blue MB tex interior is in amazing condition down to its, 356 like, moulded blue floor mats and blue inertia reel seat belts, its been stored from 1982 and is one registered keeper, a doctor who bought it in as a personal import and its covered 72000 and comes with its original service book, hand book, log book and import documents etc all in the original wallet.