Ok, So I went for the British Parts bushes - call me cheap if you want
My very first investigations showed that I only need to change one (the lower) of the two bushes (RGX100960) on the pivot arm.
When I took it all apart I found I needed both - even though, originally, the top one did not demonstrate the same wobbling problem.
Because the other bushes looked bad I thought I'd buy the other bushes (central one RGW100020) and the two outer ones (RGX100970) too.
When they all arrived I went for it taking the watts linkage off.
Firstly I realised that you really do need some big spanners - the access is just not easy for sockets:
For the RGX100960 and RGX100970 joins, the nuts are 21mm and the bolts are 19mm
The RGW100020 is held to the chassis with a very long 21mm bolt and two 24mm nuts.
(The 'inner' one is done up to torque, the other seems just to be a captive nut - holding a length of wire in place behind a washer for some reason)
For the 21mm heads, I ended up using a 7/16" W (1/2BS) spanner as I do not have a 21mm spanner (!!)
I was lucky that my 24mm socket fitted - your mileage may vary!
If one of the spanners for each joint is a ratchet spanner it makes it a lot easier!
Doing this job I realised that the 230Nm on the central bolt is 'very stiff'.
I ended up using a blow torch to heat the nut and a length of scaffold pole on my socket wrench to 'break' the nut - I've never done that before!
Doing this nut back up requires a significant torque wrench - you may struggle with space under the car when you do this nut up if the car is only on ramps!
When it was all apart, I discovered there wasn't a hope in hell's chance of shifting the old bushes using just my vice - I needed to use the 10 ton press at the local garage!
In the end, I only changed the RGX100960s - the 970's just would not fit - I broke one trying to get it in. As a result, they're going back and so is the 100020 - I didn't want to risk damaging that one and not get a refund.
Other gotchas were that you have to take the exhaust off its final mount to be able to bend it out of the way to apply the torque wrench.
The joint with the chassis on the upper arm is difficult to get a torque wrench to - 140Nm might break any obvious universal joint. Wobble bars might be a good solution or you can just wing it by trying to do it up as tight as the one on the other side by hand.
So, in summary, you'll probably need to replace more than one bush, you will need access to a big press and a 230Nm torque wrench. You will also need a nice big breaker bar to crack the nuts, 19mm and 21mm spanners (7/16"W) and a deepish 24mm socket (check this fits before you start)
Oh yes, you need to support the discovery on the chassis using stands for most of the work - except for the final torqueing when it needs to be standing on its wheels - probably on ramps (nice tall ones so you can wield the huge torque wrench!)
Lastly, the bolts are, supposedly, specially lubricated with wax. They can be reused but you cannot replace them with standard bolts.
The nuts I took off the central bolt was a nyloc though I could not see this stated anywhere in a manual. In the end I reused the same nut (!) you may prefer to check if yours is a nyloc and replace.
If you're going to have a go yourself feel free to ask me any questions - I'll try my best to answer them.
