If you're talking about a set of new barrels rather than sleeving, the expense may be too great given the value of the guns. I owned a pair of A&N boxlocks. Decent guns, in proof, no thin spots, no pits, etc. In the original motor case. Made by Webley & Scott, so essentially a W&S pair with the A&N name. At which point you have to ask, how much are a pair of Scotts worth? Individually, a very nice W&S 700 12ga can be bought for $3,000 or maybe less. Throw in something extra for a pair vs two individual guns (although pairs in the States don't seem to command much of a premium, if any); a bit more if they're cased. A new set of barrels would almost certainly leave you upside down.
Champlin Arms recently had a pair of Wilkes boxlocks on their website. Totally redone, by Wilkes: New barrels, new stocks, gone through and refurbished. In the case. The price was somewhere around $12,000, if I recall correctly. If you add up current prices for new barrels and new stocks, that would exceed the asking price for the guns. However, once you have them, they're still British 12 bore boxlocks, on which the market is fairly soft at present. Again, you could buy a couple of Scott 700's and come up with a "composed pair" for a lot less. (That being said, the Wilkes pair is no longer on Champlin's website, so they must have sold.)
