Labour are 7/1 to win. That's very long for a two horse race.
I think Corbyn has performed well and will be secure in his position after defeat. He probably won't go to 2022 because of his age, but I imagine he will see out Brexit and make the socialists' grip on the party more secure before he anoints a successor.
Labour surely won't "win" but a hung parliament is 3/1. Still an outside bet, but not impossible.