Why no town mark on this piece?

I have a fiddle thread pattern silver egg-spoon, 105cm long. Date letter capital M for 1807, but no town mark. There is possibly the remains of a now illegible maker’s mark to the right of the hallmarks, and a journeyman’s mark, but no town mark. How come?

London and Exeter in particular frequently omitted their town mark in the early 1800 period. It seems to have been most prevalent on smaller pieces and may have been an anti-fraud measure - making it impossible to cut out and transfer a hallmark from a small tested piece into a larger sub-standard piece, the larger items being known to have the town mark.

Phil

That’s really interesting Phil, many thanks indeed. I’d like to know more about how the British assay offices worked. Did they really test each and every piece? And how? Did they scrape some metal off the piece? If you know of any literature on the subject I’d be grateful to know. Many thanks , as always.
Nick