I'd say that judging by the photo, the current price of £127 is already a lot more than it is worth so wouldn't touch it with a barge pole. Not only is it in poor condition, it's very old and many of the parts are obsolete, having been replaced on newer Bromptons by far superior components.
My own Brompton isn't in much better condition - in fact, it has got to the point where it would cost more to repair it than it is worth. It is still rideable, just, but really is on its last legs. I don't mind though - I've had it more than 10 years (and it was second hand when I bought it) and have done a lot of miles on it. I just wish I could afford to replace it.
Here's a list of what's wrong with my Brompton, which might be a guide to what problems you could expect to encounter when buying an old model from
ebay:
• Head tube stretched so headset can no longer be made to fit snugly (this is due to rotational forces under heavy braking due to the long steerer column/stem)
• Seat tube deformed so it's impossible to securely clamp the seatpost (this is my fault for not replacing the shim inside the seatpost when it disintegrated)
• Rear hinge shot to pieces (normal wear and tear; it has been replaced twice before, an expensive job requiring specialist tools)
• Big dink in rear wheel rim, probably not entirely safe to ride but not cost-effective to repair given the many other problems with the bike
• 'Arms' for eazy-wheels broken off (due to rust)
The rear hub still works well. The great thing about those old three-speed hubs is that they are almost indestructible, and they are surprisingly easy to maintain too - I used the traditional schoolboy method of taking it apart to see how it works. You may find that the one on ebay only needs a bit of a clean up and some fresh grease. Beware though, I damaged the cone on the non-drive side of mine when I accidentally over-tightened it - it still works fine but just needs care when reassembling.
The current Brompton chainset is a spider with a replaceable chainring. The one on ebay has the old style non-replaceable chainring. I had to replace mine some years ago when the chainring sheared off the crank.
I also had to replace the left crank after the original one snapped in half when pulling away from the lights one day! (To be fair, it had a dink in it that had probably created a weak point that allowed it to crack.)
The original pedals were binned some years ago after the bearing in the folding LH pedal disintegrated. I use SPDs on my Brompton now.
I see the one on ebay has the original foam saddle. That was a really nasty piece of work. The saddle that comes with new Bromptons is much better. My Brompton is fitted with a Brooks B17.
I have also replaced the brake levers on mine with the newer version, which are infinitely superior. The original brake levers are truly awful. The one on ebay has the original brake levers.
Maybe I should put it on ebay. It looks like there are plenty of mugs out there willing to pay silly money for dead bikes.