Beer-battered fish burger

Ingredients

• Tartare sauce
• 3/4 cup whole egg mayonnaise
• 2 tablespoons lemon juice
• 2 tablespoons finely chopped pickled gherkins
• 1 tablespoon finely chopped capers
• 1/2 teaspoon grated lemon zest
• 3/4 cup self-raising flour
• 1 cup chilled beer
• oil, for deep frying
• 500 grams boneless, skinless firm white fish fillets, cut into 8
• 4 turkish bread rolls, halved, toasted
• 2 tomatoes, sliced
• 1 bunch rocket, washed, trimmed