Hiya M, good to see you on Rootschat again, hope you are well

(For anyone reading this thread, William is my 5 x great grandfather too)
The trees claiming Thomas to be William's father have no sources attached - apart from other Ancestry trees

I have searched and cannot find who William's father was. William's marriage to Sarah Innocent in 1798 is a transcription only with no mention of his father. I have the original image of the banns which doesn't show father's names. I'm sure you have all of this already.
But you never know, maybe a clever Rootschatter can help.