Ask the builder to send you the Fluke results from the installer. If the structured cabling was installed by a proper data contractor (unlikely), then 9 times out of 10 they will Fluke test each cable. If they did it, they will be able to send you a .pdf report with a full breakdown of each pass, pass* or fail.
Let's be honest, the cabling will be chucked in by an electrician and probably tested with a generic £5 Amazon jobby purely for wire map. It won't test for resistance, insertion loss, return loss, cross talk etc.
Worth asking the question.
Excel Cat 5e LSZH is pretty much the industry standard (not the best but not the worst). As long as the sheath is purple, not black - as that would indicate external grade cabling, which I believe can only run internally by about 5m?
Over short runs in the home, Cat 6 and Cat 7 is pointless, stick with Cat 5e.