Combine the wine and watermelon in a blender and blend until smooth.
Transfer to a freezer-friendly container and freeze until slushy-like in texture, at least 5 hours or overnight.
Loosen the mixture with a fork.
Combine the sugar, water, lime juice and tea bags in a small saucepan over medium heat and simmer, 2 mins.
Remove it from the heat and leave to steep until cool, 30 mins.
Discard the tea bags.
Combine the slushy rosé mixture and sugar syrup in a blender and blend until smooth.
Pour the cocktails into glasses and garnish with the diced watermelon and mint.
TIP: Depending on the size of your blender, it might be trickier to blend the cocktail mixture all in one go. If needed, simply blend the cocktails in batches. Add a splash of water or cloudy apple juice if the blender struggles to get going: this will make blending much easier.