Developing that point further, for better or worse we have a voting system that is made for two-party politics and we have two main opposition parties. Therefore there is a choice to be made by voters whose main aim is to vote against the government.
There is no way a split vote is going to unseat a majority of nearly 23,000 or even ones much smaller.
Labour may have come a distant second in 2019, but as I said before, with those sorts of majorities "second" doesn't count. You may as well be third, fourth, etc. There was an unspoken agreement that Labour in N Shropshire would give the Tories a clear run; the opposite has happened in other seats. Sir Ed thinks mind you that there's no need for a formal pact as "voters can work it out for themselves" but that's slightly disingenuous. It isn't "just" the voters who comply though but the parties too: however that's the love which for now at any rate dare not speak its name.