I make a very similar home-made version, which works out at 7.5 syns for 100ml - still a bit high but who's ever stopped at 50ml of Bailey's? I like mine quite strong so you could use less whisky and substitute for something else that's syn-free (as long as it's not something too watery - the 'lighter' evaporated milk is already less creamy than the full-fat stuff):
300 ml whisky (use Tesco Value whisky - it's £5.04 a bottle, 40% abv and very mild-flavoured)
1 x 410g can reduced fat evaporated milk
Good quality instant coffee to taste (1 use 3 heaped teaspoons of Kenco Millicano, and I use just ordinary teaspoons but they're American ones my husband brought over and they're rather large - if using a measuring teaspoon you may want 4)
Dissolve the coffee in enough hot water to make a thick liquid essence - about 50 ml is enough. Add sweetener to taste. Allow to cool a little. Mix in the evap milk and the whisky. Decant into a bottle. Makes about 750ml for less than £3 and will keep for a long time ......... if you don't drink it!