I had a quick search and find that there is still an Ashton & Sons listed as builders at St. Ives near Huntingdon. Maybe a family connection from a bit back as I suspect like bushveld that it will be a 'Hardwear Shop' type gun. Nothing wrong in that as it was quite common practice for rural hardwear shops to advertise guns with their names on that were made in the Birmingham trade and that makes them a devil of a job to research. St. Ives is very close by and hardwear trade to building trade is not such a giant leap. Another useful source for information of this kind and one that I have often used is the local museums. Huntingdon has one but called the Cromwell Museum because of Oliver Cromwell's association with the town but they will cover most general stuff and have street directories from way back that should provide a clue. I have always found them most obliging. Try https://www.cromwellmuseum.org/ Good luck. Lagopus.....