I believe they're the "candy cane" pattern twist steel. Obviously there's a lot of factors, but overall does that mean they're "no good".
My dad says he'd shoot it, but I'm not so brave... I think he's actually more dumb than brave in this case, but it's a fine line.
Hy says we should rig up a remote trigger set up, and wrap the barrels with rope to contain any flying debris. Then fire 90-100% power black powder loads. Then un wrap the barrels, and if there's nothing wrong then we should be good to shoot like 50-65% loads without fear. I don't know though. Seems kind of risky.
Are there any other proof houses outside of England that you could send barrels to, to be inspected and tested, etc?