Bearmach have been selling the adjustable one for well over a decade (I bought one 10-years ago and they had been out for a while even then).
Below is a copy of a post I put on another forum a couple of months ago.
About 10-years ago I replaced the A-frame ball-joint on my ex-MOD 90 for a Bearmach adjustable one (DIY without the use of a press) and now all this time later I have recently been able to detect a clunk on take-up so I thought it was time to do something about it. At the time of purchase I realised that there weren't any instructions about how to adjust the balljoint but looking at the great big slot in the top I reasoned that it was just a case of screwing it around but I would worry about that when it happened.
For easy access I removed the balljoint & housing and having placed it in the vice I knocked back the two locking-tabs and sure enough the slot could be tapped around until any play was taken up (when off the vehicle with no load, play cannot be detected but when in place it can) and re-locked it. Back on the vehicle and off for a test-drive and no more clonks. The whole job took well under an hour, excellent!
Firstly thumbs up for the Bearkach ball-joint, after 10-years of use it has only now required adjustment.
How come it wasn't corroded up and adjustment it was so easy? When I fitted it (remember I did this at home without the use of a press) I covered it with liberal amounts of Waxoil so when I cleaned it off today it came up almost like new. Needless to say Waxoil has been re-applied and hopefully it will be another few years before I have to look at it again.