It dun't happen inside the uk as our items are mostly bar coded so know what they is. Items that ain't dun't miss oot because we charge vat on total spent, if the seller is vat registered. Yer could setup a till that scans bottles to identyfy them and add up the import tax and vat.
They will want to charge for booze coming into the uk to protect our own markets. Several options. If they can identify it or cross reference it to a look up table then they can charge on a scale. If not then charge per bottle fixed rate or by type, vine or beer etc, is a simple alternative. Wot ever method they use needs to be easy to carry oot at the docks.
Eye dun't know wot options they will use.
To answer your last line, nor do we, so far we haven't had to find out and we sincerely hope we don't!
In any "case" it'll only be starting next year.
If we do get checked next year I'll let you all know. That is if we bring back a lot of vin next year, we may not, but then again we prolly will as we always seem to need to!
I note that this is all designed, i.e. the bar and QR coding, for use inside the EU. so they may well not give a monkeys about the alc content for buying, selling and transporting around the EU.
I am not sure it is done to protect our own markets, we don't exactly make a lot of red wine in the UK. I think it is quite simply, as it always has been, yet another way of taxing the drinking classes.
As I have tried to explain, the look up table would have to be massive and constantly updated.
It is too late now as we aren't going to any more vineyards but next time we go to one I'll ask them about it, and hope that can answer once their roll eyes have finished. Cos I bet most of the small ones will see it as justa nother complete pain in the rear.
In fact I may email one as they are more or less friends now.