Welcome Kittycat! You may find it easier to request supplies like nappies, feeds etc. rather than money, but you will really need to sort it out before you start. The cost of having a baby should have been considered by your DD before starting a family, and you will be saving her a lot of money by providing childcare.
I am fairly comfortably off and don't have GCs on a regular basis, but know I spend a fortune when I do.
Guilt at feelings of resentment
UK State Pension - Is it really enough?




As I said ^^, we didn't need any payment but the other granny has been a widow for years, has a very small private pension and likes her holidays! I suspect they give her petrol money and she always stays for her evening meal whereas I came home to eat with DH.