Satoshi's last forum post was Dec 2010, I believe.
Satoshi continue to communicate with developers in private for some time after.
In April 2011 Satoshi emailed Gavin (and in part criticizing him for failing to credit other contributors work on Bitcoin). Gavin replied that he would be visiting the CIA. Satoshi never emailed anyone else again.
It was in April 2011 that he replied in email saying that he had moved onto other things. The wikileaks move to allow donations was a large part of his separation, but I'm certain it was also the stress of managing so many new people (even good teams, also spammers, etc) where anonymity made it more difficult for him to help.
edit: If they never accept the payment, then the default judgement should be appealed.
They don't actually care about this judgement, they want Cobra's identity so they can harass/threaten him and/or fabricate false evidence in an attempt to steal the domain. Last year they offered him $10 million dollars for it, unsolicited, as an opening offer and they seem to have been making it clear that no isn't an option.
The challenge here is that the UK system seems to have no avenue for cobra to defend in these actions without doxing himself, which would expose him to worse attack. Fortunately, the UK's power of bitcoin.org is appears to be minimal.