In a large bowl, mix together the flour, paprika, cayenne, salt and pepper. Whisk in the beaten egg and then bit by bit whisk in the 7up until you have a nice smooth batter. Pop in the fridge until ready to use.
For the red cabbage, mix all the ingredients together well and pop in the fridge. Same for the cucumber salsa. Really nothing tricky about knocking these up!
Peel the avocados into a bowl and add the lemon juice and a pinch of salt and pepper. Mash together. Add the mayo and sour cream and mix well. Put in the fridge until ready to serve.
Put a large saucepan on a high heat on the hob and pour in about 1cm of vegetable oil. You need to get the oil really hot, so could take 5-10 mins.
Take the batter out of the fridge and cut each Basa fillet in half length ways.
Once the oil is really hot, dip a fillet in to the batter to coat it and carefully lay into the frying pan. They only take about 3 minutes on each side to cook through and get a crispy batter. Be careful when turning the fish and only do two in the pan at a time. Put the fish on some kitchen towel to soak up any excess oil.
Warm the tacos through according to packet instructions (I was going to make my own, but sometimes life is too short!).
Put a spoonful of the avocado mix on to each taco, top with a piece of fish and the cabbage and cucumber mixes.
Notes
Nutritional values are based on one of eight tacos.