Anytime? But possible morning: Mia/Open
Now with an actual legitimate reason to be sneaking around the photoshoot, Mia is there to visit Frankie- her impromptu date at the viewing party last night. Flirting is one of Mia's favourite sports you know, and since a certain groundskeeper (who was not 'hers' even though Nat teased her) hadn't come round the niffler enclosure yet, Mia had to have fun flirting (and more later when Frankie wasn't working!) with someone.
Also, at some point she took advantage of the location to go check in on Nat as she hadn't had much chance to speak with her the night before after the Art & Soul started.