Tried calling London Overground and got no reply so emailed them - response as follows "Thank you for contacting London Overground. We have received your recent correspondence and aim to send you a personalised reply within 7 working days. If we are unable to answer your query within this time, we will keep you updated about the progress of your case until you receive a full response. Unfortunately we currently have a large volume of cases to work through and our response will take longer than usual. If your contact is urgent, you may prefer to give us a call on 0343 222 1234, choose option 5 from the menu and then ask to speak to the London Overground team. We are open Monday to Friday 0900 - 1700 (except Bank Holidays). Please mention to the team that you have already written to us. Please note that we are currently working on correspondence received prior to 7 January 2016." So will report back when I get a reply in about a month's time!