Plain flour in the UK has a lower protein amount which contributes to the dough strength, type of crumb and texture of your pastry, in this case. Plain flour in the Unites States for example has the same level of protein as Bread flour in the UK so the best flour to use here will be 175 grams / 1 ¼ cups bread flour. This will help you ensure a flaky pastry and making it easier to shape without being flimsy which is often the feeling of unbaked dough.