After my previous post concerning replacement of all rear bushes with Polybush items, I can report the job was completed today, and the annoying knocking emanating from the bottom shock absorber  bush has disappeared, only to be replaced by another less audible knock which, on reflection may have been there from the outset shielded from my shell likes by the louder shock absorber bush failure noise. Wondering what this could be?. On a brighter note I can report the ride characteristics have improved immensely and I cannot detect any variation in ride quality, after reading members comments regarding a stiffer ride after poly renewal I was a little worried that the smooth ride would be something akin to a dodgem car, however my worries were unfounded as no loss of comfort so far are  has been evident. I await your suggestions as to what the new irritating noise to the rear could be. Regards all.  

Hi

Have a good look round the boot, make sure there's nothing floating around the spare wheel

also I had a strange tapping noise, ended up been those rear seat cable pulls, mine use to just float around and sort of bounce between the carpet and boot hinges, making a tapping noise

ended up putting black velcro round them and sticking them back to the carpet

cheers

Joe

Cheers for the suggestions Joe, covered all bases as regards to loose boot items, definitely  seems to be coming from the wheel area, me thinks one of the link bars, sway etc.