Mortgage application and cashback credit card

I'm looking to apply for a new mortgage soon as I'm hoping to move house in the next few months. Just tidying up finances in preparation....I currently have a cashback credit card which I use to pay for just about everything I buy and pay off in full every month.

My question is, should I stop using the credit card so there will be no balance on it when I do my mortgage application or is it the fact that I have access to the credit regardless of whether I'm using it that mortgage applications are based on?

Thanks :)