So - you have James Snell bn 1769 in Richmond with father Henry. Do you know mother, or did the baptism register only give fathers name, as some annoying do!
Dont try to leap straight from this to a birth for a Henry. Go one step at a time.
Are there other baptsims with similar details which look like siblings for James? That might give you an idea of when Henry and Mrs Snell might have married. James may have been the eldest, or may have been the youngest of 14 (for example) giving a wide range for the possible marriage.
Then, consider that marriages traditionally took place in the brides parish, but the couple more often than not settled in the grooms parish, if his work was there. Not a hard and fast rule by any means, but worth considering depending on Henry's occupation.
So look for the marriage not only in Richmond but in neighbouring parishes.
Hope that it at least confirms of Henry was a bachelor or widower, and see who witnesses were. You wont get much more from a marriage in that era.
But hopefully by then you will be in a better position to consider possibilities for Henry.
