A quick Google makes me think its the DRC, especially since it only sounds like the front right and rear left that are knocking, which I understand are the 2 linked ones as the go cross the car.
It just feels like theirs no damping when hitting potholes or bumps, is this what DRC failure feels like?
Should we get any warning lights if that is the case?
The warranty I have on the car DOES cover shock absorbers and struts, does that mean its likely to cover the repair if this is the issue?
Also on a lighter note heres a pic I took on the A66 at the weekend going to Cumbria with my plate on

