How long was Dilys late?

M: Dilys, I told you to be here at 7: 00 o’ clock, but it’ s 8: 30 now. Why were you late today?
W: I overslept and missed the bus.

M: How about seeing a film this evening?
W: When?
M: It begins at 7:15. We’ d better get there at 6: 50.
W: Oh, sorry. My mother will leave for London this evening. I’ m seeing her off at 7: 00 o’ clock.