Bake potatoes on a tray in hot oven for 30-45 minutes -- until knife-tender. This can be done the night before or ahead of time. Cut each potato into 6 or 8 wedges depending on the size.
Heat 3 inches of oil in a deep fryer or a deep pot to 375 F. Begin by frying half the wedges at a time for 4 to 5 minutes until crispy and brown. Take out and drain.
In a large mixing bowl, combine the rice flour, baking powder and salt. Make a well in the center and gradually pour in the beer whilst whisking to combine the dry ingredients and forming a smooth batter. Spread the rice flour for dredging on a plate. Dredge the fish pieces in the rice flour and then dip them into the batter, letting the excess drip off.
Submerge the battered fish into the bubbling oil for 4 to 5 minutes until crispy and brown. Remove and drain the fish with the chips on paper towels; season lightly with salt.
Serve wrapped in a newspaper cone with lemon wedges and/or tartarsauce.
To prepare the tartar sauce, combine all tartar sauce ingredients in a small mixing bowl. Makes about 1-1/4 cups. Chill before serving to let the flavors combine. Serve with fish and chips and some fresh lemon wedges.