What this actually involves
A progress report and a payment claim are written by the party being paid. We go to the site and record what stands there: the stage reached, the workers and materials present, defects that can be seen without an engineer, and how that compares with what was reported. For finished work we check whether it was handed over, is being used and is being looked after. For equipment and vehicles we go through the list item by item against tags and serial numbers and ask who answers for each one. It is a record of what was seen on the day, with photographs to prove it, not an engineer's certificate.