Thanks for all your replies and suggestions, it is interesting to hear other peoples points of view :)
I don't know what I said or what I did, but I handed over my bank details to her, asked for £50 a week, and her 1st 2 weeks went in with no quibbling! :o Maybe it is cos her glandular fever returned and she was appreciating Mum! ;D
The original idea was to save the money for them, and give it back when they left home, sadly circumstances have changed that idea, but who knows what may happen down the road, am going to keep a record, and if we win the lottery.................... ::)
If I have an argument on my hands next time, I shall do as suggested and give her a list of our outgoing living expenses, and suggest she could pay a 1/4!! :D Its funny really, she has just done a 6 month stint volunteering in Tanzania, the I really appreciate Mum/food/ home/car/ washing machine etc. bit rubbed off very quickly!!
Thanks for all your help
DP