Complex sentence: The Hewitts (see below) are one attempt to avoid this by requiring hills to have a relative height of 30 m, thus excluding the 125 least prominent Nuttalls from the list.
Split into simpler sentences: The Hewitts (see below) are one attempt to avoid this. The list addresses one of the criticisms of the Nuttalls by requiring hills to have a relative height of 30 m, thus excluding the 125 least prominent Nuttalls from the list.