Yesterday, because of a reduced service, the last Mildmay service from West Brompton to Stratford (22:25) was cancelled (it actually started at Willesden Junction). I had planned to catch this train to West Hampstead and then onwards to St Albans. The ticket I had was only valid by this route. Fortunately, I arrived at West Brompton slightly earlier than anticipated, so was able to catch the one before. Had I not managed this, would I have been able to use an alternative route (i.e. Underground) for no extra charge or would I have been expected to pay out and attempt to claim back later?