Mine did that and it was strut bearings. Although I still have occasional knock from the right hand strut. Bearing and bushes fixed it 90%. I must have something else not quite right. I'd say the issue you have is strut bearings. Make sure you get good brand ones, cheap eBay bearings will fail within six months.
It would be worth biting the bullet and replacing every bush in the front end that hasn't already been replaced. I couldn't believe the difference it made, and the noises and knocks that it eliminated.