Well the parent in question was hugely apologetic when she saw me - I think she realised she was being unfair and having a hissy fit over nudda - nothing!
She told me she will have to have a 'frugal Christmas' (her exact words) as she is paying me 1 day holiday pay - I told her pay them both later in the year, but she said she'd pay 1 day now, 1 later... I am sorry, but she cannot have a frugal Christmas because of £50? Plus the guilt trip hasn't worked.
I am glad I stayed calm and didn't react, but responded.