Student Finance query

so I am applying for my third year student finance
I legally am registered and live at home with my mum however stay at my long term girlfriends house.
when applying for student finance, the form asks me where I will be staying/living for each term. I will not be financially depending on my girlfriend but I do stay here a lot. If I am to clarify I stay here what information of my girlfriends will they require, and will it negatively impact on how much finance I receive. (do they take into consideration my girlfriends income)
Also what evidence can I provide that I will be staying here if I'm legally registered as living at home?