Butter or oil an 8" square tin; set aside.
Put sugar, vinegar, syrup, and water in a heavy saucepan (cast iron if you have it). Be careful that your pot is big enough, because sugar has a tendency to boil over. Gently heat the mixture, stirring with a wooden spoon, until sugar has dissolved & syrup has melted. Bring to a boil, cover & boil for 3 minutes, then uncover and boil until temperature reaches 285-degrees F on a candy thermometer.
Remove from heat & stir in the baking soda, mixing well to allow bubbles to subside a little. CAUTION: once you add the baking soda the mixture WILL bubble up quite a bit. Again, make sure your pot is large enough or it will bubble over the sides. The baking soda is what gives it its light airy texture.
Pour into oiled tin & leave until just beginning to set. Mark into squares with a lightly oiled knife. Leave to set completely. Cut or break into pieces.
Combine chocolate chips, shortening & baking chocolate in 2-quart glass micro-proof bowl. Microwave on HIGH 2 minutes. Using wooden spoon, stir through to melt.
Dip honeycomb pieces into chocolate, covering completely. Let cool on waxed paper. Wrap individually in waxed paper, twisting the ends together, and store in an airtight container.