Hi Christine
For John RULE who married Grace BRAY 7 May 1803 at Illogan, children appear to be William 1804, James 1805, Ann 1807, Grace 1809, John 1811 and Mary 1813 (years approx). Grace BRAY was bapt 27 Mar 1780 at Illogan, d/o James BRAY & Grace FRANCIS. Grace BRAY nee FRANCIS died 1828 and left a will.
James BRAY & Grace FRANCIS had at least 6 children: Mary 1774 (m 1793 to Thomas RULE b 1764 s/o John RULE & Jane BAUDEN), Anne 1776 (m 1796 to Christopher RULE b 1769 s/o John RULE & Jane BAUDEN), James 1783 (m 1811 to Frances RICHARDS), John (mentioned in his mother's will), Joseph (mentioned in his mother's will) and Grace 1780 (m 1803 to John RULE). WIth so many connections to the John RULE m Jane BAUDEN family, it might be theorised that the John RULE who m 1803 to Grace BRAY was also closely connected to Jane BAUDEN.
As to Peter RULE who m 1768 Illogan to Margaret COCKING, I had the following children - Peter 1771 (must have died in infancy), Peter 1773 and Henry (or Henery) 1787. I don't know of any other children to this couple. The Peter RULE who m 1768 was bapt 1744 at Illogan to John RULE and Catherine PERKING, I reckon.
You said "Peter Rule b. 1756 m. Margaret Cocking". If that was so, he was only 12 years old when he married, so I think your statement must be in error.
I think you need to look more into the BRAY family, especially the connections to the several RULE sons of Jane BAUDEN.
Cheers
Peter