CJ, I was planning to take a shot at this one. I agree with "reincarnation." I've seen good restoration work, but don't recall having seen better and rarely this good. I'd call this "best" work and have absolutely no difficult to believe that the hours expended number in the hundreds.
A & N is a Brand Value level three name; that is the easy part. The gun is a flatback SLE, back action with the lump through the floor. Along with the engraving and wood grade, this leads me to believe that this gun "C" grade. It is not an exact match for any of the guns in the 1914 W&S wholesale catalogue (reprint). It comes closest to the W&R 4th Quality, but lacking a third fastener, can't be a Screw Grip. The serial leads me to guess it is a just pre-WW I gun; anyone have an A&N dated from the books in this (#57555) serial range? If I have my facts straight, the base gun would have sold for something like £36, the ejectors were an £8 option, and the Whitworth barrels (it does have Whitworth barrels, doesn't it?) were an additional £8 for a total of £52. The Premier, W&S's "best grade" gun, was £90 with Whitworth barrels; the Premier Imperial, the extra finish gun, would have been £120. So, we have BV3-OQ4 at this point. Looking at Current Condition of "pristine," BV3-OQ4-CC1 = $7959; BV3-OQ3-CC1 = $10,458. This seems to be a reasonable range for the value of this gun if it were in OE pristine condition.
Current Condition is better than new, but still restored as it is not OE. Restored is CC5. BV3-OQ4-CC5 = $2396 --- somehow, I don't think that is right. So, what is CJ offered? If he got the gun for "near nuttin'," and has 500 hours into it (I'd suspect more), an offer of $10,000 would put his time at $20/hour!!! Boy, I dunnno!!! Are gunmakers allowed such an extravagant wage???

CJ, my one wish is that your next project will start with a gun of higher OQ grade. Really a skillful job. It is uplifting to see all these skills concentrated in one individual. I suspect you are the embodyment of the vision of the handwork gunmaker.