Typically, you aren't going to find an English gun, of any quality, that was rebarreled, by, say Marlin, Remington, or H&R. It will have been done in England, and passed proof.
Since there exist guys like Thorny, who would shy away from a Holland gun, rebarreled by Westley Richards, or Powell's, or, whoever, these guns can represent a heck of a buy-you are going to shoot the gun, right?
Alfred, Kirk, and some of the other guys from Europe, who are living here, have rebarreled a few English guns as well. Maybe they don't have reproof marks on them, but, I'd be willing to bet they are quite sound for everyday use, and would be bargains as well.
You are at the level (cost, being an object) that you are buying the gun, and not the name. You are approaching it by hiring an expert to appraise the gun, a sound formula for success, assuming you lack the expertise to risk it on your own.
If you have no intension of selling the gun, anytime soon, you may get a fabulous buy on a liftime's worth of great quality gun. Selling it, soon after purchase, might sting the purse a bit, however. Good luck, and let us know how it goes.
Best,
Ted
