Always use a metal tape measure when taking the measurements for your new blinds (cloth ones can give inaccurate measurements).
Once you have decided to use Roman Blinds as your window dressing, the next step is to decide whether you want them installed inside or outside of the recess of your windows. Be sure to check if there are any obstructions: If your blind is obstructed by catches or handles, it can snag on them potentially causing damage to the blind itself or to the operating cords on back of the blind.
Please send through your measurements in centimetres, rounded to the nearest millimetre.