Thanks, Rick. I've attached a couple of extra pictures that I had handy. The barrell starts off round and becomes hexagonal from the middle towards the back, not damascus, and the muzzle bore is smooth. So not unfortunately an P53 barrel, and ramrod was locally made

but you are absolutely right about the trigger guard

- even though its been decorated its a perfect match for the Enfield ( I'll come clean here and admit that I had not noticed this even though I'm sitting with a 1956 3-band Enfield not more than 4 feet from my nose

)
Since the guard and lock at least are both from the British gun, I guess this was built from recycled parts, at some time after 1860. Since there is a neatly cut space for the missing part of the trigger guard it must have been complete when the gun was put together.
Do you know what the five rolled metal inserts on the butt were for - decoration or was there a practical purpose?