Yes, you are right - his history was indeed chequered. You found this information much more quickly than I did! He was married in Bavaria on one of his trips there with racehorses; his wife Anna was from Pfaffenhofen, Bavaria where their oldest son, also William, was born in 1849. Anna died young in 1856 when their family was very young (they had 3 children - William, Anna Marie and Emily Anne b. 1854 - Emily being my ggrandmother). For some reason, William 1802 did not raise his children after his wife died - his sister, Anne Burrows also of Tardebigge, raised them. My ancestors thought that Wm. had died at an early age as well, I have only recently discovered that he lived to be quite a good old age in fact.
I also find no formal record of William's birth in 1802 - this information was recorded by family records only as June, 1802. I also find no record for Wm's parents - this is the point in my research that I approached you, in the hope that your John may have been a brother to my William and thus making that connection, but it wasn't to be that easy. Good luck with your further research for your family,
Mary