Belen
I've had a look through the Sigglesthorne BTs this morning. I'll write up my notes and send them to you by a PM, if possible.
I worked from 1700 to the 1790s. Some of the pages are very difficult to read - they seem to have suffered water damage or something similar - so I can't swear I've picked everything up. There are a couple of entries for a Henry Coultman early, then the John Coltman you have, with more children to his name. He was living at Catfoss when he married - doesn't help, it's part of the parish. They seem to vanish after a while and there is no grave under Coltman or Coultman extant at Sigglesthorne. (There are early graves there, including that of my own 6 x great grandfather, who died in 1761).
The Snows continued to live there and I found their grave in the MIs.
You might want to take a look at East Riding archives - I searched the online catalogue for John Coltman and came up with something from 1769, referring to a John and Henry (his brother, I assume) Coltman were at Meaux.
Let's hope the PRs are a bit easier to read, though I would lay bets on it.
More detail anon.
Joyce