I'd be more interested in what the frame is built from and the longevity of this if it was a forever home. Do the high quality window suppliers just use the same size rebate with deeper beading for 2g as opposed to 3g?
My nans been in her place over 30 years now. Got the rosewood upvc they put in when renovated before moving in. Changed a few units but the frames still serviceable now. How long are the "good quality" 2g Windows expected to last above the standard upvc product? Got the standard upvc in mine and got a good air test result.
I think when it comes to Windows be careful not to overspend and don't believe all the hype.