Anyone know what tool is needed to remove the firing pin from this gun. I think it could be a whitworth spanner, but I am not sure.
Thanks.

On most a small open end wrench should do the trick.

Bob, There dose not seem to be any set standard for the across flats of the hexagon screw in bushes that retain firing pins.I have at lest 10 custom made wrenches sold/supplied by gunmakers for removing these bushings. None of which fit the same hexagon! You can try the adjustable wrench approach all to often the jaws tend to be too big as a result they slip and damage the hexagon.My recomendation is to purchase a small inexpensive wrench that you can by filing, open up the jaw to fit the hexagon on your Scott bushings.

They used to call them magneto spanners, small open ended wrenches,different sizes on the same spanner, purchased in sets. Made for setting points when we had points in out car electrics. I'm sure you can still get them from automotive supply houses. One of mine is perfect for removing percussion nipples. A couple will fit firing pin bushings. Very handy to have, mine are.
Mike

I have two long series 1/4" drive sockets that have fitted everything that I have come up against in the recent past with a hex nipple and they are 1/4" AF and 7mm AF. Even if they are slightly loose if one holds them very firmly and dead in line with the axis of the thread they spin the nipple out just fine.
I find that the 1/4" AF nipples are often very restricted in clearance around the nipple so I have turned this one down to about 0.020" wall thickness and now have no problems with it. It pays to invest in a nice little 1/4" drive tommy bar to go with these sockets as you can then really get your hand wrapped round it and it isn't off to one side as with a ratchet.
The square headed nipples used by Purdey and others are a different problem completely. The trade nipple key for these is often simply a two sided wrench on a turnscrew handle. They are really easy to make from a long series socket as above of the correct or just under AF size. Then simply file a slot straight across the socket leaving 2 opposing flats only. Only file as deep as you need to fit the nipple as the tendency is to splay the flats apart in use.

Toby,In my collection of nipple keys I have one interesting key, that suggests there must have been an industry standard for the sizes of hexagon. This key is marked;"Bayliss and Son patent, Number 1" Unlike the bell ended socket keys normally ecountered, this key is infact a miniature ring wrench. It is fitted with a black wood handle to match those found on turn screws and other implements some times found in gun cases.
Possible patentee Bayliss and Son; gun rifle and pistol maker, 1863-1866, Upper Priory Street, Birmingham.