I got this recipe a few years ago off the TV, I think it is a Darina Allen( brilliant Irish Chef / teacher) recipe.
560g/1¼ lbs Brown wholemeal flour
560g/1¼ lbs plain white flour
2 rounded tsps of salt
2 rounded tsps of bread soda(bicarbonate of soda)
750-900ml /1¼-1½ pints of sour milk or buttermilk.
You should be able to shape this into a 6 inch round shape.
You won't have any problems with leftovers.

Enjoy !!