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.