My dad's just had a composite door fitted and it's really draughty especially around the top corners, along half the length of the bottom, and in the middle of the rhs especially where the latch is. Re where the latch is the draft proofing stops either side of the metal casing so how can it ever be draughtproofed, is that a design fault? Any clues from the photos if it's something that can be rectified?