Can't help with rent/ rates and chair renting agreement (contract for services), but you do need to obtain your own Public Liability/ Treatment Risk insurance.
There are numerous policies/ offerings available but be careful in choosing the right product with the right claims wording (Claims occurring) - ask for clarification. If it is the inferior 'claims made' basis you will only be insured on the basis of continuous cover with the same provider (no breaks), which means you must be insured by them at the time of the alleged incident and when the claim is registered (unless a discovery period has been enacted by insurer). All too complicated. Seek advice/ guidance from the provider.
Premiums are based on qualifications/ experience and treatments provided subject to a standard statement of fact.
Good luck