I have a clinic so offer them the chance to come to me and if not advise that travel is charged at the same rate as the session costs. I don’t then charge for mileage but it is then their choice what they want to do. I learnt early on that the odd 20 mins here and there really adds up especially if you get caught in traffic and reduces the time available for appointments. It wasn’t feasible to carry on like that as you need to to maximise contact time to cover all costs and earn a decent salary.
Hope this helps