By Kevin Maguire It may be back to the future with a very different ending to Margaret Thatcher’s 1983 landslide for Rishi Sunak when it is the Right rather than Left that is terribly split in 2024. Back then, Michael Foot’s Labour and the Roy Jenkins-David Steel SDP-Liberal Alliance together polled 53% of the votes and, fighting each other seat-by-seat, gifted the Conservatives a thumping 144-seat majority. The split on the centre-left was the decisive factor in that bitter three-way contest more than four decades ago, not the Falklands War a year earlier, which is regularly and mistakenly ci…