First of all cover your kitchen side in flour and roll out pastry till you have got to required size for dish twice (for bottom of pie and top), making sure thickness is equal. Add the first layer of pastry to the pie dish, then drain the tunas and put into a mixing bowl. Then add chopped olives, sweetcorn and onions(optional) while adding cans of chopped tomatoes and tonnes of tobasco sauce yum! Mix together and add more tomatoes if too dry. put mixture into pie dish with pastry already prepared and cover over top with secondary pastry. Put in oven for 30- 45 mins 200 c (depending on size of pie) and serve! Hey presto!