Henry's Last Hurrah

1 1/2 oz sweet sherry
1/2 oz Scotch whisky
1/2 oz dry sherry
1/2 oz dry vermouth
1 tsp Drambuie Scotch whisky
1/4 oz lemon juice
3 1/2 oz lemonade

Pour into an ice-filled wine goblet, add a half-slice of lemon, and serve.