Hi Nigel. I have started a Winn/Wind surname project to follow these issues among other Winn/Wind problems. We have found that there are lots of reasons for name variations, please check the page.
https://www.wikitree.com/wiki/Space:Winn_Name_Study.
BTW, Winn is not the only name that has changed over time for the same reasons - accents unfamiliar to those recording the name etc etc.
Mostly the name variation can be that the parish clerk/priest or whoever who was most likely NOT from the area and was trying to interpret the name as spoken by folk that have quite different/broad accents even within a county or parish. The folk getting a baptism in those times were rarely literate so were unable to correct the written name.
There are now I believe, several origins to the Winn/Winds of both yours and my family just within Durham county. It can be a name derived from a location eg a winding lane "Wynd", or a windy location, or even after the odd "lord" with a surname similar. BUT, mostly it seems to be interpretation of a spoken name, that was simplified over time. Remember that some the Durham Winn/Winds may also have a Netherlands origin, something I am still researching. I see on both your and my line Winn>Wind> Winde and Windd. Some records are even in latin that further complicated the issue.
BTW, be careful of the William Wind born 1731 line. As I mentioned, there are TWO William Winds (Lamesley and Lumley).
As noted in the other answer. I am using surnames and other names as they appear in Baptism/Births with Research Notes if needed to explain the variation. I have found some where the only "fit" is a baptism of a slightly different variation to say a marriage or for children. Confusing, but we are making progress.