Dear [INSERT COMPANY HERE],
My name is [INSERT NAME HERE] and I am a young filmmaker in London, currently auditioning for my short film [INSERT NAME HERE].
Because this film is very low budget, and I am putting all of my own money into the production, I am looking for an affordable space for auditions. Your building is exactly what I'm looking for and would be an enormous help to the production. I don't have a great deal of money to compensate for utilising your audition spaces but I would be happy to offer you a credit in the movie and my eternal gratitude. I am willing to hold these auditions at any time that is convenient for you- so if you have any slots available between [INSERT DATES HERE] then that would be amazing!
Thank you for your help!
Best wishes,
[INSERT NAME HERE]
[INSERT PROD.CO NAME HERE]
[INSERT PHONE NUMBER HERE]