This has been said plenty already, but:

Does Rayner mean "working class" like the hundreds of thousands of young people working under the living wage in cities with no hope of ever owning a home...

... or does she mean older voters who bought their home(s) outright decades ago?

Because these are both groups that identify as working class, despite one being destitute and the other pretty financially comfortable.

One of which is more racially diverse and incredibly progressive on sexuality and gender.

The other which tends towards social conservativism.

Here's the kicker - There is literally no way to land your social policies in a way that appeal to both groups as they are right now.

You can only pitch to one and try and convince the other to come to you.

Hint: The Tories already have one of those groups in their stable.