It is generally the case that the full time address has to be given so unless the two of them are living with you full time she should not be using your address even if it was her childhood home. I would be very careful about agreeing to this and if I was advising you I would say that you should not agree to this. Is there any reason why the London address that is your daughter's actual address can't be used as that would be the truthful one to use on the application? However, under no circumstances would her husband have any right to live at your address unless you agreed to that. I hope that helps. Please leave a positive rating so that I am credited for my time.