Combine the hot water and honey in a small bowl, and stir until fully mixed.
Chill the honey syrup mixture in the fridge until you are ready to prepare your cocktail.
When you are ready to serve your cocktail, combine the honey syrup you made earlier with the freshly-squeezed lime juice, and stir to roughly combine.
Add this sweetened honey-lime mixture to a shaker tin with ice, along with the 2 ounces of gin.
Shake the contents until fully combined, roughly 15 seconds.
Strain into a chilled glass over ice, and top with the soda water.
Stir, and serve cold.