Best one to use is to look at her for a bit in a passing kind of way and ask:
“Do I know your sister?”
Then they HAVE to answer either yes or no. If they answer yes just keep going with it, eg:
“Slightly taller than you, blond long hair?” Again just go with the flow. Act surprised when they say that the girl you’re describing isnt their sister and just introduce yourself and ‘to say sorry for wasting her time’ offer her a drink on you. You order quite an expensive one and pay with a £20.
If they say no- ask if their sure and repeat the process above. If they keep saying no then just offer to buy them a drink anyway seeing as you’re at the bar and pay again with a £20. If she’s with a mate (as long as its not a bloke…) buy her one as well and make small talk as the barmaid/barman is mixing the drinks. Then ask if they fancy a dance and concentrate on the one you want. If poss have a mate be the fall guy and go distract the mate as you get jiggy…
Problem solved.
Let me know how it works out.
BARNOWL