There is a Banrock low alcohol wine which is a similar strength and that's 16 syns for the bottle. Haven't tried it myself and probably won't because if I'm having wine I want a decent strength one!
The easy way to work out the Syns value for things like this, with no free food allowance, is to find out how many calories it has. Divide the number of calories by 20, and that gives you the Syn value.