Aaron Borbora wrote:
Did you ask about continuing beyond Hatfield and getting a cab/lift home
from the next stop? Not and ideal solution, but I might well have
considered it had I been in the same situation.

I didn't think that at the time. It's easy to think of all the things
you could have done after the event.

Certainly calling the police on my mobile would have been a good idea,
rather than using the alarm, although the train would have long since
departed by the time they arrived (Potters Bar to Hatfield at that time
of night is only a few minutes) as it wouldn't have had any cause to
stop and hold anyone onboard.

Jonathan