Agree that Next to Normal and Operation Mincemeat should be at the top of the list.
I have not seen, but there are fans of the new special Starlight Express and the longer playing ABBA Voyage. Also, Stranger Things - but it's coming to NYC next March.
Fiddler on the Roof at the Regents Park Open Air Theatre has received some excellent reviews and apparently "sunrise, sunset" begins right around the actual sunset time.
Mischief Movie Night might be worth a go - from the people behind The Play That Goes Wrong and other "goes wrong" shows. An improvised "film" each night. Only to 1 September.
Two Strangers if you get Gift and Tutty.
For something different:
Posters over on theatreboard seemed to like Viola's Room by Punchdrunk - an immersive experience.