On the letter box there should be two screws which join the inside part to the outside this along with the silicon maztic which will stop the water getting through the door.You may have to cut the scew bolts to the required thickness of the door.
alex fakirk.
September 2008
Stick it on with waterproof Silicone Sealant either clear or white,you'll find it at any DIY store,the same stuff you put around sinks and worktops.
Rich
September 2008
Automatic Answer
We may have found other answers which could help you.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix windows and doors.