One other thing I have in my favor: Company S (formerly Company B) did not deliver me a copy of the paperwork in a prompt manner despite promising to do so. It's been a week, and I have yet to see any of it, despite having asked for a copy to be routed to me. HR droid mentioned that photocopier in office was broken when I signed paperwork.

Company V (formerly Company A) cannot help me in this situation - they have too much to lose by starting a turf war.

On leaving early from the contract: Since the department I'm in is being shut down in six weeks (I was brought on to help close it up) EVERYBODY is assumed to be looking for a job - the only requirement that was made of me, by both the HR person and my manager, is that I give two weeks notice - no bad blood at all is what they've said to me.

Not that I'm believing the HR drone now... But my manager has actually been very straightforward with me, and hasn't BSed me once. Pretty decent guy, just sounds like there's not much he can do.