wheel vibration

All, I hope you can help with what might be the culprit of a very annoying problem. When I drive the E220d estate (2016 plate), I can feel a very slight steering wheel shake/vibration. I've had it in a couple of garages, and no one can seem to find the fault. They say they've tested the bushes...

Our beloved W209 had a bang on the front offside wheel / wing and ever since it has a bad vibration only on that wheel, noticeable at 40mph when braking and getting worse under braking at 50,60,70mph. It seems worse when going downhill. The vibration can be felt through the brake pedal a little...