Hi. You won't be able to carry it in your hand baggage but also, I'm not sure it's worth it from a cost point of view. Liquor is pretty cheap in the supermarkets in Bequia so I have never bothered taking duty free into SVG.
You will be able to carry duty free liquor on SVG as the liquor stores are past security.
Definitely OK to bring duty-free on SVG flight. I have always picked up a big bottle of Mount Gay on the way through, definitely cheaper.
I stand corrected. But still won't bother!
I think you're allowed to bring in one bottle duty free per person coming into SVG. That being said, we've brought in "several" bottles of wine when heading to Petite St. Vincent thru Union without any problems. While beer and rum are readily available, wine can be hard to find in the Southern Grenadines.
You should be fine in Bequia as mentioned, plenty of selections there. Try abottle of Sunset Rum, good local stuff.