It is with those over 60 that Labour is suffering the most.
https://twitter.com/EuropeElects/status/853923247385128960
That can be tied, in large part, to Brexit. Which enjoyed it's greatest support among those in that age group. The Conservatives now offer a united, coherent, pro-Brexit policy. Hence the ridiculous margin. A new Labour leader would not make an perceivable difference with that group. Not as long as Labour remains divided over Brexit.