Broken bed - who's liable?

Other

My tenant advised the bed had broken. It is an iron framed bed - the slats have come away down one side and she currently cannot sleep on it. Further, the central column is bowed and one of the legs has badly scratched the wood floor. She is only 5'4" and about 8 stone and says the slats just went one by one. She has a boyfriend who stays occasionally but he's not that big either. I bought the bed brand new at the start of her tenancy 18 months ago (admittedly it was a cheap one) so she is the only one who has used it. It cannot be repaired and has to be replaced.

Who is liable to pay for the replacement? me as landlord, or her as tenant?

Thanks