Just installed a new upvc window, and am having trouble because one of the openers catches on the strike plate for the locking mechanism at the bottom when I'm closing it. There's a rather large clearance between the top strike plate and the opener, however, so it looks like the thing isn't properly aligned. Does anyone know if there's likely to be a simple way of realigning it? It's a typical horizontal type opener, with regular hinges (not easy clean or anything like that).