To be fair, that was what was advised when Labour won. Ignore the naysayers while you are getting on with it (the majority helps). Then come out swinging closer to the election.
However given the (apparently) rapidly sinking IQ of the Great British Public, ably assisted by the tabloids of doom, I can easily people saying that Labour deliberately improved the economy just to spite Reform.
Remember this is the country where people didn't care about the economy when they voted Brexit.