I seem to have the same symptoms as I had about 18 months ago and since fitting a cheaper front wishbone, than I would normally have acquired.
If I jab the brake pedal the car will lunge slightly forward and I previously worked this out to be a worn NSF wishbone rear bush. I had the MOT done last week and the guy said the same bush had a little play in it. I usually only fit OEM parts, but on this one occasion I left it to the mechanic to order in and it was a cheaper product.
The morale of the story is, fit cheap and you'll be fitting twice!
