HI again Rocket

As I am always guessing at British gun values I would like to inform myself better, I mean its easier when you have a holland holland in your hands to find a value but its all the others in between.. can I ask you where you get the info on brand value and such...?
Is there a book or is it from market values and auctions that you go by...? and any idea whether this was a W.C. Scott action..?

thanks again
Sean