"I wonder how the UK govt would have behaved in your case given their total fecklessness about everything."
Probably throw you into jail, no questions asked, headlines splashed all over the papers followed by investigation and muted unpublished apology.
The agencies involved wouldn't have a clue! How do I know this? We know someone that claimed family allowance (don't know the new name - apparently it's now called Child Benefit) for their 2 kids even thought they had ALL left the UK and didn't move to a country were they could continue to claim child benefit.