easy to fix,first of all mesure letterbox size as there are many sizes of letterbox's,then visit north west hardwares website and order the same size if you can get one or a bit bigger if you cant,then take old one off,you can see screws when the plate has been opened,take these out inside and out and replace with new,if you have to buy a bigger one you will have to make square hole in your door a bit bigger to make it fit.hope this helps
shaun www.sdwupvcrepair.co.uk, August 2008
