(Research): The Antiquities of Nottingham has a section on the history and ownership of land at Car Colston, Nottinghamshire, which is about twelve miles from Bunny. It records that William Henson purchased the land in the early years of Queen Elizabeth. Therefore he was an adult in the 1560s.
Working backwards from William son of Gregory, we know he was born in 1578, and Gregory was probably at least 22 at the time of his birth, which would place Gregory's birth in around 1556. Gregory may plausibly have named his first/only son after his father. However, working back from Alice married in 1610, her grandmother cannot have been born much later than 1570, which knocks about another four years off at least. Say 1550.
We now know William was married in 1547. That would suggest William senior was born around 1525.