Hello,
Many thanks for your email,
We can’t do a frame cut out, but we can provide handle spacers to bring the handles out further forward so when you open and close the handle this does not hit the frame,
https://www.blindsbypost.co.uk/blind-parts/perfect-fit-handle-spacer?fast_search=fs
You still require the 25mm clearance around the window so that the frame will fit around this and handle is not in the way of this 25mm clearance.