The polls I referred to are about Reform generally being the biggest threat to Labour. Haven't seen any polls regarding this by election, but the argument I've seen is that the votes for anyone other than Nigel last time outnumbered his votes, so those votes might well go to Count Binface since no other major parties are fielding a candidate. Which seems wishful thinking, but is a possibility.

Overall, there isn't really a great outcome for Nigel here. He either wins, which isn't much of a victory given the (lack of) opposition, or he loses, which is devastating for his credibility. Regardless, I still think this is a bigger story than you originally made out.