An RICS Full Building Survey Report (also known as a Level 3 Report) is the most comprehensive and in-depth type of survey. It provides the buyer with a detailed analysis of the properties condition and involves thoroughly inspecting the property and reporting on issues, summarising defects and potential problems. It offers advice on repair options, the costs involved and what might happen if they aren’t repaired.
It's the best choice for larger, older, unusual or listed properties as well as those that need renovations or change of use, such as a barn conversion, hat require more detailed attention in the report.
At the end of the day you are paying for an experienced registered professional to give you their opinion on the integrity of the property you are hoping to purchase.
To be safe we simple recommend that you ensure the surveyor is registered with a relevant professional body such as the RICS and that they have 10+ years experience.