Here. Phil Willis has issued a typically robust and bluff rebuttal:
If offering temporary accommodation to one's children is wrongdoing, then there is something seriously wrong with our society.
Allowing my daughter to use the sofa-bed in my one-bedroom flat hardly appears to be abuse of the system.
As for refurbishment, painting the flat once in 10 years and carrying out electrical repairs, I believe no reasonable person would regard as excessive.