genearlly speaking the show is about 2hours 10 from begining of vertigo, to the end of Vertigo, It seems likely that the curfew will be 10.30pm, (or possibly 11pm if you are unlucky)
How long it takes to get out all depends on how near to the exit you are, i wanted to leave Twickenham in a hurry, so as the encore Vertigo started, I moved to the back of the pitch , near the exit, and it enabled me to get out quickly, the visuals for Vertigo are quite impressive, so its worth seeing them from the back anyway.
Having said all that, as the roof will probably be closed, and there will be no sunlight at the begining of the show, vertigo with the lightshow might be at the begining of the set, with another song to close it.
Good luck with your train.