So, first things first. Evaluate your own provision and write your self-assessment report for your own organisation's benefit first and foremost to ensure leaders and managers know the provision, understand areas for improvement and direct resources accordingly. If you're in England, Ofsted are clear; they use the SAR to support their planning and risk assessment. It is used less during inspection under the Education Inspection Framework so please don't think they are looking for you to write it in any particular way.
We hope this short resource helps to keep it simple when writing evaluatively.