Hi John, I suppose you have tried trolling on some German genealogy sites? Most have English language options. I did not have much luck on my own visits to those sites but I found them to be very interesting. It is possible that the name was changed but I am wondering if it was, why it was?
My husband's paternal line came from Germany to the US in the late 1800's. They crossed the continent, living in different states. eg Iowa and Idaho, ending up in Washington State, and then up to B.C. Canada. They did not change their name until the starting of the First World War when there was a lot of bad feeling towards people with German names.
Even then, only a couple of the sons of the original couple changed their names to what sounded close to their own name:Gruhs to Bruce. Original name was Bernhardt Gruhs. He only changed his first name, casually, to 'Ben.'
Maybe Brindley was a true name? Perhaps some inquiry into what was happening at that time, 1700's, in what was then 'Germany' might give a clue into what he was up to. Or maybe some pushy female Brindley, proud of her name, talked her German husband into changing his name.:-))