UK Landlord Forum / Life

Hi can I have some advice please
Our tenants renewed beginning of August for another year - today she says they have split so can we amend contract to just her and she will be going on benefits to help pay.  We have never dealt with benefits can we request to see proof she can pay alone or what would you do?? I don't mind if she can pay solo but I would like proof as she has three kids so don't want to end up evicting them. 
Any advice is greatly appreciated
Thank you
Emma