Took Sport to local service centre, the following is what they did.
Check for play, none found, check suspension arm bolts, steering rack bolts, ball joints and links, all ok. Road test again, noise still evident, only from side to side. Recheck lower arm bushes, all ok, check anti roll bar brackets and mounts, found 2 nuts holding brackets have not enough tension. Re-tightened anti roll bar nuts. Road test no knocking heard.

SO much better so smooth, a pleasure to drive again, superchip upgrade monday  Range Rover Vogue Classic 3.9 V8 1992
101 Forward Control GS 1977
Range Rover Sport SE 4.4 V8 2006