Third year undergrad tutor-how much to pay

[IDontGetOutMuch]

Our y11 daughter is starting tuition with a lovely 3rd year undergrad we know. He wasn't sure what to charge. I don't want to under or over pay. He's obviously not a qualified teacher, but does know his stuff and dd enjoyed the trial session today. In our area, £30 ph seems standard rate for qualified/experienced teacher.
Any suggestions on a fair rate?

Winter of 2019/20 we had a lad doing a postgrad who was very happy to tutor for £15ph. He drove to our house.
His thinking was that he was just "going over stuff" to help my dc with her A level understanding.... didn't really need to 'prep' - she would get her books out and ask him to re-explain something she wasn't confident about.
He also said it was more than twice as much as he was earning in his bar job.

If you expect them to have expert knowledge of the curriculum and come with work prepared then it needs to reflect that extra time.

That's really helpful, thank you. He has suggested £10-15 so I think I will pay £15 per hour since he's someone we know and dd is happy to go there. I forget how low wages are for student jobs. Full disclosure-I tutor and charge double that, but I have a degree, teaching qualification and 20+ years' experience!