HI all i have a 3.0 55 plate x-type sports premium which i bought with 30,000 miles on, a year later and now with 50,000 miles i started noticing a rear knocking or rumbling noise coming from rear and i am pretty sure it is from rear everytime i drive over any uneven road service, it seems more noticable from left hand side specially when going right and weight is more on left and even worse with people sitting in back, i have changed rear anti roll bar bushes which i thought cured the problem but alas though the noise doesnt seem to be as evident it is still there, i then changed the drop links but has made no difference, on reading some threads on here i gather my problem could also be either lower control arm bushes which im not even sure what they arm or it even could be the lower bushes in the rear shocks, if anyone has any advice on a cure to stop this annoying rumble and how hard a job it is to do i would be very grateful