Classic rear knocking
 

So I finally got fed up with the knocking sound from the back end, emptied the boot from jack spare wheel etc, went for a spin and still the same, looked underneath and gave rear droplinks a wiggle , should these have any sideways movement while all four wheels are on the ground ?

then looked at the shocker and i thinks its leaked, so im going to swap this out, is it an easy job to do? wheel off, rear seats out, disconect brake line, undo bottom two bolts and top three ?

do i need to replace top mount at the same time ?