I'm not sure its honestly that much to do with Rayner herself, more the fact that she is a senior Labour figure and the Tories are so buried in sleeze that they will grab anything that helps play into the "they're all the same" narrative that people on the right love to push.
I mean its nonsense, but it won't stop them trying, they are desperate.
That's about it, it's not just the narrative the right want to push, people who should know the difference say Labour are just as bad.
It's important for Labour to hammer this point after Raynor is cleared, the whole country knew the Torys were going to get nasty and it's important the public should expect more of this over the rest of the year. Police resources used to investigate a possible £1.500 claim which had already faced scrutiny and cleared while many Torys get away with Millions in tax evasion, not avoidance, yet a excuse of honest mistake I forgot is accepted.
We can expect more of this and the public need to be aware of it. the more the Torys try it the more they lose the respect of the country.