RSJ Steel Calculation for Extension

I need a professional to calculate the steel requirements for a small extension (under 20 square meters) using an RSJ. The loading will be light (e.g., a single story roof). I have specific dimensions ready. we are in the process of selling our house. The work on the extension was completed in 2012 but a building certificate was not issued. York building control require the calculation for sign off. I have the plans showing the size of steels used.

Key requirements:
- Accurate steel calculation
- Experience with RSJ and light loading
- Structural engineering background preferred

Ideal Skills and Experience:
- Structural Engineering Certification
- Previous RSJ projects
- Detail-oriented and precise