Airport Tax: Usually stated in your ticket, and it should be as the following:
Any departure from London to Iraq the passenger tax duty will be GBP 80 for economy class.
Any departure from Manchester to Iraq the passenger tax duty will be GBP 84 for economy class.
Any departure from Sulaymaniyah and Erbil to London and Manchester will be USD 15 or equivalent.
Any departure from Baghdad to London will be USD 13 or equivalent.
The price you pay to your ticket issuer will be including all taxes.