What conditions would be necessary for the Labour Party to win the 1983 general election? Who would lead the party, if not Michael Foot? Would the Falklands War have to had been averted, either through diplomacy or by it simply never occurring in the first place? How different would Labour policies have to be from the 1983 manifesto, so as not to scare off the middle class? How would Thatcher and/or the Conservatives become so unpopular that a turn to Labour be necessary?
No Prime Minister was more passionately hated by the majority of the British people than Margaret Thatcher.
Even with a divided and disorganized opposition and a victory in the Falklands the Tories still only got 42.4% of the vote (less than 1979).
The important thing to avoid would be the split in the Labour Party in 1980/81. The election of Denis Healey would be the best way to avoid that.
Second of course is no Falklands War. Many senior Tories were thinking of removing Thatcher before the 1982 Party conference if things didn't turn around soon. And they wouldn't have.
Assuming she wasn't removed the British economy recovers a little in 1982/83 but unemployment is still rising (and would continue until September 1986) and she dare not challenge the unions head on.
She may put off an election until 1984 in the hope lower inflation and a recovering economy would save her. It probably wouldn't.
A 1983 election against a fairly united Labour Party and no Falklands war would lead to a Tory defeat. The amount of hatred was too strong and without a victory in war she would have little to show the electorate except lower inflation than 1979. This would be at the price of over 3 million unemployed and a few actors and pop stars staying on in the UK because of the tax cuts for the rich.