Might be something close to a 100% premium for a Brit 28, based on prices for the 700 series Webley & Scotts. But the trend today is for 28's with longer barrels, and as far as I know, all the 700 series 28ga guns came with 26". Too bad.
Re Brit 16's, I don't own one currently. However, remembering as best I can, all the ones I have owned were marked with a 1 oz proof. That's not to say you'd want to shoot 100 clay birds with 1 oz loads in one of those guns, or even a round of skeet. I reloaded low pressure 7/8 oz for targets and saved the Brit 1 oz loads for pheasants, etc.
