Ask the quotation to describe the completed work at each stage, any inspection included and the decisions left for a later instruction. If the intended layout changes, discuss the effect before buying more components. The owner should be able to understand what has been completed without relying on an eventual project that has not yet been authorised.
Before later work begins, provide the current installation information and applicable approvals. Keep the completed-work records together, while identifying the dates and extent of each alteration. This makes it easier to assess the actual fence after changes instead of assuming the original plan still describes everything on site.