not very clear pics esp when blown up.....lock and hammer looks to be kyber pass copies...
remove lock by taking out the two side nails and lock should come out . might have to cock hammer.
is they are makers initials or names there....if english they should be but none if foreign made.
when lock is out check lock mortice to see if its rough cut out or new looking.
british guns were very well made whereas kyber pass versions were just hacked out so to speak.
the barrel is definately not british maybe belgian and made to fit.