Problem with window frame?

I had some replacement double glazed windows and frames fitted last year by the same builder who built and fitted the windows in our new extension.
The windows in the extension are fine but we're encountering problems with the replacement windows in the original part of the house.
The problem has been there since fitting but since the winds arrived within the last week or so it's been more apparent.

This is the style of window we have



Notice the green arrow? It's pointing towards a gap of around 1 - 2mm in places on the hinged side of the window



The wind seems to be breaking through the outer seal and as the inner seal falls short of the frame it's making all sorts of noises to a degree where both the wife and myself didn't sleep at all last night.

My guess would be that the frames were a very tight fit which caused the edges to twist slightly.
Can any window fitters / makers confirm that it shouldn't be like this?

I called the builder last Monday but he's still yet to come and have a look.
He was FENSA registered if that helps?

Thanks for any advice.

You don’t need to be a window fitter to confirm that it shouldn’t be like that & your own common sense is correct! Difficult to say the cause & it could be down to either manufacture or installation; if the fitter didn’t use packers either side of each “through fixing”, between the frame & the wall, the frame will distort when the fixings are tightened.

Whatever is the cause, it’s a fault & the builder should come back & rectify it; if he won’t co-operate look to FENSA for some leverage, it’s supposed to be why they are there & I've have had sucess with OFTEC, the oil regulatory body! I always prefer to use a company prepared to offer a 3rd party, independent warranty then you should also be covered if they go bust which seems to happen with monotonous regularity!

Thanks Richard.
Builder came back this morning to take a look (I was at work but spoke by phone with him). He agreed it wasn't right and contacted the manufacturers. They're sending somebody out to take a look at the problem with the builder so between them they should come up with an adequate solution.