Sorted this issue. Thought i would share for anyone else with similar issue.

On a recent motorway trip, had a rattle from rear on return journey. Thought it was parcel shelf mount. Turned out to be the rubber donut thingy on the rear suspension. The one that sits on top of the shock absorber with the integrated washer. Basically, the washer had been smashed out through the rubber mount so there was nothing stopping the shock from going up into the strut tower. I couldn't fix it or get a replacement. So what i did was get a washer with same size centre hole to fit over the shock absorber, but the rest of the washer was the same diameter as the rubber mount. I put the washer on the shock, rubber mount on top as normal and fitted the suspension back as usual. No way it can be pushed out again. I put another washer the other side while i was at it just to be sure. May be worth doing as standard by anyone replacing suspension. 

Edited 21 May, 20188 yr by Eviljohn

Think that is how it is meant to be 

The set up i got in the box was Bilstein b4's. The integral washer was very small and just got smashed through the rubber donut. Still being a relative newbie to anything mechanical, i had no idea this was a thing. Just thought i'd post this for anyone in a similar situation as i haven't seen anything about it anywhere else. 

If i recall when i done mine i carried the original washer across for that reason so you did the right fix 

 

The small washer is recessed on one side to sit on the shock before the thread i think

That's exactly what happened. I didn't have the spare washers to hand though. Had to go find them elsewhere.