Help updating our letting agent agreement documents

We are a letting agency that requires assistance in updating all of the main legal documents we use: Landlord Terms of Business, Contractor Agreement, Tenancy Agreements, and Holding Agreement

Please advise on the cost per hour and how many hours you think this work will take you. We already have versions of all of these documents, we just need a legally trained person to read them over and make sure that they are legally binding, protect our company from liability, and "fair" as determined by the OFT guidance.

Thank you.

Kind regards,