Copeland election irregular and unlawful? There's missing information, this article suggests:https://skwawkbox.org/2017/02/26/exclusive-electoral-expert-copeland-by-election-unlawful-count-suspect/
Also in Copeland, the preferred candidate, ex Sellafield employee, wife of a Sellafield employee, popular homeless worker and campaigner was, for some reason, not elected as the labour representative. Which seems a shame, really.
Also in Copeland, there were boundary change shenanigans which brought Tory Keswick into it's constituency.
I'm not saying any of this helped or hindered. But none was picked up in the press.
And it's not like there hasn't been enough coverage...Even the Guardian....front page, all of pages 4 and 5, some sniping p12, more than half the editorial, some letters, too....(not counting the bits I've missed) saying...guess what? And May looked impressive yadda, yadda, too.