I've recently watched Andrew Berry's excellent series of five videos on making a pendant setting in 9ct gold for a 10mm trillion amethyst and then setting the stone.

This piece was said to be for a customer who was coming in to the shop to pick it up "in the next day or two", and yet no mention was made of putting any hallmarking on the item at any stage during the fabrication or after the stone was set, and none was visible on it at any stage throughout the five videos. The item was clearly over the weight threshold for gold.

Can anyone say what I've missed? When did the item pay its visit to the hallmarker? Even assuming the customer wasn't literally coming in so soon as the next day or two, Assay offices ask you not to send in items with stones already set, and, from what I've seen of other people's experiences, it would be foolish to do so.