windows not closing fully

What often happens with hinges is that they seize through corrosion, then bend - this moves the pivot point and the window doesn't fit any more. If you can remove the hinges, unseize them and straighten them out you may be able to reuse them - just remember to give them a drop of oil occasionally.

I had problems with some of the windows in my house, which seemed to be due to wear in the hinges rather than seizing. In my case, the gap was more like 1/4" than a whole inch. Depends on the quality of the hinge, but on mine a small amount of wear prevented the pointy bit (attached to the casement) engaging in the 'V' (attached to the frame). I replaced with screwfix hinges. Sadly, that didn't improve things, but on closer inspection I discovered that the screwfix ones were handed, unlike the ones I had removed, so I swapped them around and all is good.

hth, Jon.

I had another look and it is nearer 1/4" than 1" as I originally said.

Your problem sounds exactly the same as mine, so it looks like replacement hinges will fix it.

I presume the Screwfix ones come with fitting instructions?