I don’t know the procedure, how easy it is or if there is a minimum limit but you can get local tax refunded in the country of purchase, much like the duty free shops we have here for London tourists. You will still have to pay duty & UK VAT but at least you won’t be taxed twice. You could chance your arm but, personally, I wouldn’t be tempted to smuggle it in. Customs take a dim view & are nowhere near as lenient & user friendly as they used to be & if you get caught, you could end up paying the duty, VAT, a fine & have the goods confiscated so you end up with nothing!