Take off the top white cover where is a screw, bottom one u have got when u turn the handle.
I think wont help, that loose would be not on the screws only the handle it self, in that case you wont manage to tight, only replace the handle.
It is possible to attached the upvc profile lengh to the top of the frame, speak to your local windows manufacture to get one.
The previous post suggestion seems to be less work and cost so would be better that way.
I believe you are replacing a door inc the frame.
You need to measure the wall to wall beside the frame and then add on aprox 20mm( depend on type of a hinges).
About a cill, needs to be below the floor level( it depend of door type).
Measure the hight from the top of the existing frame...
Maybe the keeper of the night latch needs to be fitted away of the frame with some sort of packer(should be inside the lock box).
Make sure you have fitted the seals proper way.
Another solution, throw away the seals and fit the brush strip instead?
Hi, you have to take off wedge gasket on the glass, (should be inside)
take off top and two verticals beads and put any plastic packer between the top of the glass and the door leaf on the handle side, somebody need to lift the door up by grab the handles so will make the gap for packer.
I belief the windows outer frame its not insulated with expanding foam,the gap between frame and wall, you can do this from outside, make sure its foam underneath the cill, obviously you have to use a long ladder.