So, here are the three sigs. The first is from 1813 administration of the estate of JB dec'd and is the sig of JB, ribbon manufacturer.
The second is of JB ribbon manufacturer, but this man was a bachelor in 1815 whilst your JB had six? children by that date. I think he (the 1815 groom) and wife Elizabeth are still alive in 1841. She passed away in 1850 aged 60 according to the newspaper and he then vanishes!!
The third is the witness to the marriage of your Jonathan's son James Bray to Sarah Bunney in 1828.
1813.JPG
1815.JPG
1828.JPG
IMHO the first and last signatures are v similar but the middle one less so, which would fit with what I want, but I'm no nearer to finding who your JB married and whether he had one or two brides (or more!).