Anyone able to help me with an evaluation of a Paradox? I would appreciate any help.

What I have is a Holland And Holland 12 bore Paradox. It is plain but in very nice condition.It has Fosbury Patent stamped on one of the barrels.
98 Bond Street on the other.

I have shot some 12 gauge shot shells in it and they appear to pattern consistently. I have not tried any slugs yet.
It would appear to me that the but stock was replaced but if so very, very well done. barrels have matching serial numbers.
So do you have an idea of value?.
Here are the only photos I have.