The style of this piece reminds me of the AyA Best Quality Boxlock (BQB) of several years ago. It certainly had the scalloped back but maybe more extensive engraving ?. Memory is getting a bit rusty for these things
You are quite right. I believe it is pretty much the same, but known as the "Best Quality Boxlock" in the UK (still available I believe). Many UK models were built to order, so there are many variations (barrel length, single/double trigger, self opening, chokes etc.)
Its a very nice gun.