As mentioned above, you should be fine with a couple of glasses of dry white wine, but should slightly reduce your insulin, and make sure you have some fast acting glucose at hand just in case. Alcohol impairs your liver's ability to raise your blood sugars while it is in your system, meaning you will probably go a bit lower. It's a good idea not to drink too much for this reason, I usually drink a maximum of half a bottle of dry white once or twice a week. And avoid dessert wines like the plague, they can have plenty of sugar lurking in them. This will cause your blood sugars to spike at first, and then the alcohol will make them crash later.
In terms of flu jab, I had mine on Monday, and did not adjust my insulin. I had the jab at midday, and my blood sugars were as follows: 12.15- 5.6. 15.34- 4.2. 17.44- 4.9 19.33- 5.0. 21.59- 5.1.
Blood sugars on Tuesday lowest was 4.5, highest was 6.1. In my experience my blood sugars don't rise, but doing some extra testing might be a good idea. My example might not be completely relevant, because I did not feel ill after the jab. Some people get mild flu symptoms, and it's possible this can cause a rise in blood sugars. Just speculation on my part though.