A different kind of Diagon/Gringott's question...

[damo]

Would it be possible to find out from a TM the approximate "last call" for Gringotts, and then join the queue near that time? I was wondering whether that would reduce the total wait compared to getting there first thing in the morning. (And for those without EE, like me, the morning approach is hopeless anyway.)

They might not know ahead of time. Could depend on a lot of different factors such as queue length, how the ride has been running, etc.