Sign a 2 page Licence Agreement
This is a straightforward document in which you commit to use your chosen office quietly and reasonably, pay your bills on time, give us a minimum one months notice before you leave, and when you leave, hand the office back in the condition you took it, fair wear and tear accepted. We commit to run the building efficiently and provide the services you have requested. It's written in clear English, with no hidden meanings, and you don't need a solicitor to advise you.