The surname Mayhew probably derives from Mahieu the medieval French version of Matthew. It seems to have been principally introduced into England by the Normans after the 1066 conquest and later from 12th century crusaders returning from the Holy Land whose decendants were frequently named with biblical names in honour of their fathers’ endeavours. Today, there are approximately 6,215 people with this surname in the UK[1].
Historically there has been an unusually high local population of Mayhew as a surname around Suffolk and Norfolk in East Anglia:

The first Mayhew identified in our own family tree is John Mayhew, a farmer who died in 1769, and was buried in Mundham, Norfolk. He fathered 12 children and our own line descends from his fifth son Isaac:
John Mayhew ( – 1769)
Isaac Mayhew (1746-1813)
Michael Mayhew (1777-1855)
Henry Mayhew (1812-1881)
Richard Alfred Mayhew (1849-1927)
Alfred George ‘George’ Mayhew (1874-1951)
Richard Charles ‘Charlie’ Mayhew (1902-1969)
Nicholas John ‘Nick’ Mayhew (1960-2021)
[i] https://britishsurnames.co.uk/surname/mayhew/stats last accessed 12 Dec 2021