HELP! Broken / Damaged window

Greenwellies_2

Hi,
Once again I know it's the wrong board but there are so many lovely helpful people here, that I feel at home here!

Yesterday my middle child damaged the hinge on our double glazed living room window.
I've managed to push it back into place and force the window closed. I could call the insurance co, but I think I can do the job myself. So what I am after is some advice from someone who has either a window fitter friend or family member, or someone who has experience of changing window hinges.

I've seen new hinges in screwfix, at worst they'll cost me £9. (assuming that they are my size)
I am quite capable of undoing some screws and putting new hinges on, but I worry about the weight of the window (top hung) and 'stressing' the new hinges.

Can anyone give me some advice?

Thanks

GW