I've just seen a house for sale on TikTok for £35000,000. I'm not sure what that proves, but whatever it is it's not a typical house price. It's in Chelsea, but that's not important either. Here's another one for £40million if anyone doesn't believe me. www.onthemarket.com/details/14025797/
Again, it proves nothing, other than that there are people with a lot of money to spend.
£500 a week per child is expensive, but not outrageous. £1000 a week for one child is, obviously, double that, which may be the rate for an exclusive nanny, but again, is not typical.
None of this is relevant to whether or not a £5000 a month salary after offtakes is a good salary though. These things are relative, and in many ways unrelated to expenses, as the are not taken into account when salaries are set. It is, in answer to the question, undeniably above average though.