Extra risk for Labour here - as you mention above, if the Tories lurched right and ate up the Reform vote that would incline a bunch of Labour-sympathetic voters to vote tactically for Labour ...

... unless Labour also flirted too much with their image of the Red Wall (think 2005-2010) and left those potential tactical voters feeling like *only* the Greens or Lib Dems would actively oppose Reform-ist arguments.