Hi stayed at Grange a couple of years ago, and yes you do notice the road noise, especially if you are not used to it (like me! lol) That said however, the site is very conveniently located, and I understand the loos etc have recently been upgraded. A pair of foam earplugs would block out the road noise (it's like a low hum - unlike my OH's snoring!!)
Stayed at the Grange two weeks ago - great site but you can here the road noise and it goes on all night OK for a short stay also beware of the entry road it is literally off the roundabout as you come off the A1M