Hi Kev
Hope this is not too late to help.
We used to clean a theatre but they didn't have showings every night. We broke it down into three stages.
Toilet/bar clean - This included foyer, ticket office, bar area and toilets as the theatre was open some nights for ticket sales only.
Main clean - Audatorium (excuse spelling!) and all above, plus all stairways (ensure you've got some very long extensions!)
Special Clean - All of the above plus dressing rooms and other areas back stage.
We were given a yearly rota of what the theatre opened for.
Good luck with your quote - let us know how you get on.
Fox