Income on joint owned property

This may be a dumb question but we are fairly new to this. My brother and I are soon to be purchasing a property where we will both live along with our mum, we will own the property 50-50. We currently own a rental property (soon to be selling) so are familiar with filling out our self assessments for the rental income but are wondering how it would work in our new situation. Am i right to assume that if the three of us were to each pay £300 a month into an account to cover all bills etc that I would have to declare £450 a month as income (my brothers £300 and half of my mums £300), and the same for my brother on his return. If this is the case would it be recommended for us to use the rent a room scheme for our mother?

Hi

Thank you for your question.
As your brother is co-owner, the expenses he pays for his share of the property isn't a consideration when calculating the profit and loss.  
We are unable to provide financial advice with regards to the income your mum pays, you will need to consider if you opt for traditional method or rent a room method.

Thank you