English shotgun?

[lowcsp]

I have recently purchase this shotgun I would like to know if it is English made and a time frame of when it might have been built. It seems to be in pretty good conduction the bore has a little pitting but looks shootable and while the hammers are not original ever thing else seems to be. here are some pics of the markings.

[Seth Isaacson]

Looks like it has Birmingham proofs but those were sometimes copied. Are there any other markings such as an address on the top of the rib?

[T*O*F]

It's an English J. Manton 12 ga export gun.  These were sold thru various suppliers like the Great Western Gun Works and others for the American market.  These are not high quality Mantons that one usually associates with the Manton name.

[Feltwad]

The proof  marks are for London for 1868 Birmngham were the same but were cancelled the same year has they were the same has London for the same year ,The locks stamped John Manton  are not right because John Manton 1752-1834 was long gone by then  the only Manton that came close was  Manton &Son 1834-1850 also Manton & Co 1828 -33 which also were before 1868, London cancelled this provisional proof mark in 1925  To me its seems that most  of the names and proof marks have been added which was common on export guns to make them sell better .
Feltwad