broken spring would be my first thought the coils on the struts can sometimes break and this leads to the symptoms you describe. if it is a broken spring replace both sides, as the other will probably follow,.
Now we have herd it agree with stu it’s likely to be worn bushes, suprised the mechanics didn’t spot it.My guess would be anti roll bar bushes they can look fine but be shot inside.
On my car they looked fine and passed the MOT but replaced them and the knock went away.
I will leave that for the real mechanics to comment on.I have the exact same problem. When I go over bumps the passenger side clunks pretty bad. I push on the car from each side on the front and it is not bouncy.
Steering wheel play
I lifted each side of the front tires and found some play. I only hear the clunks from the passenger side, but the driver side also has some play.
Passenger side wheel play
Driver side wheel play
What could this be?
Most likely a wishbone bush worn , part not expensive but a lot of work to get old one off and new one installed , you can jack up and use lever to check for play in the joint . It’s usually the back oneI will leave that for the real mechanics to comment on.
But I wouldn't drive it until I knew or preferably fixed. One side I would say bushes or tie rods both sides I would be worried about the whole steering box. but something is definitely broken
Think I've found the issue, it's the mount on the sub frame. The Bush is worn and it's a big Job to replace.Most likely a wishbone bush worn , part not expensive but a lot of work to get old one off and new one installed , you can jack up and use lever to check for play in the joint . It’s usually the back one