Jays,
this was not at al nice, the violence of the "lurch" and the bang that echoed through the car made me think, more than once, that someone had hit me or something had broken in the front suspension.
It only happened with cold roads, below 10C and if the ground was wet it was at its worst.
From April to September there was no skip, at all, so very much a tyre/road temperature issue.
