Weird conversation this lunchtime.

Me: A pint and a half of Saddleback please.
Barmaid: I'm afraid I'll have to give you two glasses, we haven't go any large ones.

Me: <after a brief period trying to fathom this> We that's the usual way, is it not?
Barmaid: Oh no, we get people asking for big glasses like that.

And no, she wasn't winding me up.