Ok so this is random but the outdoor theatre in regents park is genuinely one of londons best kept secrets. Shakespeare and musicals may to september, even if it rains they keep going.

Tickets way cheaper than west end but atmosphere is incredible. Literally watching hamlet while ducks waddle past. Bring picnic, wine allowed, dress WARM because it gets freezing even in july once sun goes down.

Book early though because locals obsess over this and it sells out fast.