Gas usage whilst on holiday?

Been on Holiday for a week or so. Before we left everything using gas was turned off. Water, heating etc. Whilst away checked app and was been charged standing charge each day, fair enough. Returned home, checked the app again, for 3 of the days we were away (8) we have been charged £1 each day? What is this for if no gas at all is been used and standing charge has been charged daily?

The app isn’t reliable. You’re billed according to the readings on your smart meter not the app. Unfortunately you can’t check the meter now for the time you were away, but it’s unlikely you’re being overcharged.