Really just to repeat earlier answers, an interest in a property can only be created by agreement or conduct. Since there will be absolutely no evidence of any agreement giving you an interest in the property, conduct is all thats left.(posted 7603 days ago)In order to get a share in a property as a result of conduct you must either pay the mortgage OR carry out substantial repairs or improvements to the property (routine decorating and ordinary maintenance is not substantial but paying for new windows or personally doing an extension would be). Therefore simply paying the utility bills wiil not afford you any interest in the property.
You could also consider setting up a rent agreement, forms are cheaply available at places like WHSmith, just make sure that whatever you pay is paid into a different account to the one paying the mortgage and whatever you do dont pay the mortggage directly!