Greg you have enough money to play with so why buy used?? Granted London guns are magical in every sense of the word but if it doesn’t fit you or was made for some one that is twice as big or half the size of you then that perfect balance is lost. And as Ted said we don’t hunt like the British hunt.
With that kind of money to play with why don’t you get yourself a gun built especially for you either at CSMC, but I know you aren’t real thrilled with American built guns, OR you can get yourself a Spanish built gun from Arietta or the like that is built for you.
Whether behind a dog or otherwise when that bird flushes you need something that will snap to your shoulder and not get hung up on a shirt or jacket sleeve.