You get to York from Malton going to Peterborough your train you were to catch is late, but the one before that which would have gone already is also late so you just get on that on. That is how works here, if you want to reserve a seat you CAN do buts its up to you. If you got to where you are going and say you are an hour late getting there to might decide to stop an hour longer and come back on a later train, you cannot do that with reservations you would have to come back on the earlier train and have a shorter day out.