Vibration woes 300tdi disco

Hi guys,

I'm getting a terrible vibration that seems to be coming from the rear end at around 55mph.
I have had a good search on here for things to try and solve the probs which are listed below

Ujs replaced
Rubber donut replaced
Track rod ends changed
New tyres and been balanced
Wheel bearings changed all round

Still getting this vibration problem, anyone got any more pointers?

i had the same on my 200 at exact same speed turned out to be my pitman arm, didnt know either thought it was my tyres till it failed mot on it changed it now its beautifull, worth a look and a wiggle may be someone else will come along with a different answer but worth a look while u are waiting

Pitman arm?? What's that??

any one?