The following information comes from The Book of the Pistol and Revolver by Hugh B. C. Pollard. The Book of the Pistol and Revolver is also available to purchase in print.
List of London Gunmakers in 1825
This is from Lieut.-Colonel P. Hawker’s book “Instructions to Young Sportsmen,” fourth edition, which deals largely with the question of flint-lock as against the new “detonator” or percussion system.
Anderson, Robert.
Baker, Ezekiel.
Bates, John.
Barnett and Son.
Barton, J.
Beckwith, W. A.
Beddowes, John.
Biven, J. A.
Blake, J. A.
Blanch, John.
Bond, E. J.
Bond, William.
Bowstead, F.
Brander and Potts.
Egg, Durs.
Egg, Joseph.
Enty, John.
Forsyth and Co.
Goff, Daniel.
Green, William.
Grierson, Charles.
Gulley, Joseph.
Hall, Collinson.
Harding, James.
Hill, John.
Homer, Thomas.
Jackson, Richard.
Jackson, George.
Lacy and Witton.
Lombard and Butter.
Leigh, J.
London, William.
Manton, John, and Son.
Manton, Joseph, and Sons.
Moore, Charles.
Mortimer, Thomas.
Mortimer, Thos. J.
Nock, S.
Nock, Samuel.
Parker, William
Parkin, Thomas.
Pritchett, R. E.
Purdey, James.
Rea, T. A.
Reynolds, Thos.
Ridley, Thos.
Ridley, William.
Riviere, Isaac.
Sherwood, J.
Smith, Samuel.
Standenmeyer, S. H.
Stevens, Thomas.
Sturman, Philip.
Tatham, Henry.
Turney, J.
Webster and Co.
Wilbraham, George.
Wilkinson, James, and Son.
Wilson, Alex.
Wilson, William.
Wright, Robert.
Barrel-makers.
Lancaster, Chas.
Fullerd.
(Of the above names, Purdey, Blanch, and Lancaster are still in existence as first-class gunmakers to this day.)