The drop of the vertical blind I need for my conservatory window is 1540mm at its minimum point from the sill to the top point of the bracket that the headrail fixes to. I am going to use a face fix bracket of 96mm x 28mm. Do I have to make any deduction
Vertical blinds for my Conservatory
All you need to provide is the total drop (minimum) from the bracket fixing point to sill, we do the rest in manufacture.
For your reference the deduction for headrail and sill clearance is 5cm but please just provide the shortest drop.
Fit the headrail on the same plane (if your situation allows) as all the other rails, do not fix on the doors themselves remember your width for doors will be the to the inside edge of the window sills.
Have you seen our Conservatory Measuring Page this should provide additional information.