Well I've checked all the UJs, greased them and the propshaft, and they seem fine. I also removed all the wheels and removed what I considered to be excessive and solidified grease, and re-seated the wheels on the splines. I have also used the car a bit more and things do seem to have improved.
IcePack - yes the car does have a LSD, a BTR I believe, and friend drove the car and said it seems fine, although he also said the 'clunking' when I push the car out of the garage could be the LSD. So the next step is to replace the oiI in the diff (it is nearly 7 years old). It seems the popular choices are Castrol Transmax LSD 75w-140, Morris Lodexol XFS 80W-140 and Red Line 80W140 GL-5 Gear Oil (does it need a friction modifier too?) - which one is favourite?