Thanks for your question.
Under 14(1) Employment Rights Act 1996 an employer make make deductions from an employee's wages to recover overpayments paid by mistake unless the employee was led to believe by the employer that the money was theirs.
Your daughter's employers are therefore legally entitled to make the deductions, so she should therefore think practically about her situation. Get her to engage in a constructive manner with them, make sure she tells the the effect that a deduction of that size will have on her financial position, that she did not realise the overpayment, plead poverty and ask them to reconsider the amount they are to deduct each month.
If your daughter is occupying her property under an assured shorthold tenancy (which she will be unless she received notice at the beginning of it that it was to be merely an assured tenancy) then the landlord may only serve a notice for possession upon here either where the rent is paid monthly and she is two months in arrears or where she has been persistently late in making rent payments.
Even after serving such a notice the landlord will then have to apply to court for an order for possession if she does not leave. Again though a policy of engagement with the landlord is probably the better view
Sorry it could not be better news but I hope you appreciate there is little point in my sugar-coating the situation.
If this has been useful please kindly click accept so that I may be rewarded for my time. It will be gratefully received and you will be free to ask follow up questions.