Discovery td5 funny banging noise!

For a while now I have had a banging noise coming from underneath my Disco.It sounds heavy like the exhaust is banging from side to side,you can also feel it!!With just a slight twitch left or right you hear this noise. BUT ONCE YOU HAVE SLAPPED IT ONE WAY IT WONT GO THAT WAY AGAIN,YOU HAVE TO THEN TURN THE OTHER WAY! a bit like something sliding side to side in the boot!!i have had it checked in a garage and all they found in three hours was nsf shocker bolts at the bottom there is a slight gap under the plate on one of them.all other bolts have been torqued. Could the compressor be loose in its box? I have a couple of hours tomorrow morning to have a nose about! Sorry about the capitals etc, the trxt box is out of view when typing on my phone!! THANKS

Confirmed, not the compressor!

Stabilizer link.......... I have to change them regulary, don´t know why

Been confirmed by Rockingham landrover as the Watts linkage!

This remained unsolved until recently. I done the front anti roll bar bushes and the links. The banging was then coming from only the back, confirmed as ball joint on a link arm. New bushes and link arms on the rear, now all is well!!!! Used genuine links as heard bad things about aftermarket!