Quantity Surveyor/Cost Estimator for GBP 50k residential project

I'm busy in my own field and a unable to closely manage a building project at my residential property.

I'm working with a builder who is known to us and who we believe does good work. The relationship is reasonable.

They don't, unfortunately, provide invoice breakdowns and I have asked them to stop work until we can work through their invoice and help them break it down so it's transparent. We are 2/3 way through the project.

I'm searching for a quantity surveyor to do approximately 10 hours work initially:

1. Proposing a reasonable, standardised format for invoicing
2. Working with myself and the builder to get a reasonable level of clarity on their invoices based on work done and materials used by stage
3. Reviewing the invoices and giving an informal response on reasonableness

The project is in the midlands, UK.