My client uses public transport to visit his clients regularly. He tops up his oyster card and can provide a statement showing top ups and journeys made. He has said that he uses the Oystercard 50% for personal use and 50% for business.
Can I treat this like I would a telephone bill by just calculating the amount of top ups he has made and charging 50% to the company or do I need to literally get him to tell me what each journey was for?!!