Hi, marp.
Some of my Brocksopp ancestors lived at Park Hall/Parkhouses, and one married a Sadler, but my information doesn't seem to quite match yours. Henry Brocksopp (1654-1707) married Mary Marriott from PH in 1681. In 1683 he was the executor and residual beneficiary of a William Marriott, husbandman of PH, and presumably acquired some sort of tenancy at that point. By the time of his death in 1707 he was a yeoman and so had a long term lease, which passed to his son William. William died in 1763 and left his real estate in Pilsley and Parkhouses to his grand son William Sadler, son of his daughter Mary and John Sadler of Allestree, (subject to various payments to other relatives).
So it would seem that either there were two William Sadlers with land at PH at that time, or you've got the wrong parents for your William. As spendlove says, it's quite possible that Parkhouses referred to an area containing several land holdings, and that different Sadlers "owned" different bits of it.
David