HSMP holder,sponsoring mother for UK visit visa,accomodation

Hi,
I want to sponsor my mother to visit uk and stay with me for 1 month.
I got 2yr visa under HSMP and it expires in 10 months.
I've enough bank balance and I'm workingfor a reputed company here.
For her to get visa, I need to show that I can arrange for her accomodation here. I'm living in a shared house and have taken one double bed which can easily accomodate 2 people. would it be feasible to say that my mother will stay with me in this room? did any of you guys did so?what kind of documents I can provide as energy bills are on owner's name and I just have the bills of mobile phone and TV coming on my name.
If its not appropriate, i would appreciate other suggestions.
thanks,
ch