I do not agree that any
sensible definition of "overnight" would exclude the period 0216 - 0637 just because the origin station (which we do not actually know!) was after midnight.
I suppose it could be argued that if you are not staying in "overnight accommodation" then you could be refused to leave the station, but that would absolutely defy common sense. Sometimes I can't believe we are even having such discussions!
For future reference though, it is worth mentioning the origin station and departure time in the opening post. It's only in post #11 that we learn that the departure time is after midnight. We can guess your origin is the same as the location stated in your profile, thought that is not necessarily going to be the case!
Does it matter? T someone who is pedantically applying NRCoC Condition 16 to the letter, in a way that was clearly
not intended, yes, I suppose so. But to someone interpreting it in a common sense way? Surely not!
Also some gateline staff in the London area would argue that you are starting your journey on the 9th, even if the date on station clocks stated the 10th, but that's another matter