Yes I have the 1851 census and John is a bricklayer. I understand that Riding Officers had to fund themselves and they needed another job as they were frequently not paid for months on end. My cousins and I disputed this one for a bit as John has never shown up in any other documentation as anything except Riding Officer?Coast Guard but the family all add up. As for 1841, I have them in a census in Norfolk. Would be interested to see that one in Portsmouth - only because they both say (at one stage anyway!) they are from that way. Will search it out. This is the info re the marriage as sourced from Ancestry (with secondary sources noted):
Name: John Parsons
Sex: Male
Marriage: 1827
Marriage Place: Diocese of Cork & Ross, County Cork, Ireland
Spouse: Mary Farrell
Source: Albert Eugene Casey, Eleanor L. Downey-Prince, and Ursula Dietrich.. Index of O'Kief, Coshe Mange, Slieve Lougher and Upper Blackwater in Ireland. 16 vols. Birmingham, Alabama: Knocknagree Historical Fund, 1952-1971.
I've gone and had a look again at Martha's death - no doubt in my mind that it is she. The combination of Parsons and Belsey is as isobelw says "compelling". But no sign in ScotlandsPeople of Robert or any of the younger children who I am having difficulty finding in 1891. Gotta love a good mystery