Also cannot at present locate marriage of George Barnes to Sophia?
In 1851 in Jane Cambridge's household Sophia was a daughter and George a son-in-law, so I deduced that they must have been a pair.
This confirms it (I copied it from somewhere else):
”George was born to Luke and Elizabeth Barnes, in Mangotsfield. George became a stone mason, then he married a girl named Sophia Bees. George and Sophia and the Mother-in-law moved to Pontypool, in Monmouthshire along with Sophia's two younger brothers, to find work. Tragicly Sophia developed cancer of the uterus and six months later she died on the 5th November 1869.
George had already met Mary Jane Bennett, the daughter of Samuel Bennett, before Sophia had died, and when Mary reported Sophia's death, she was already calling herself Barnes. George and Mary Jane married in 1870 at Llanhilleth parish church. George and Sophia had a home in Moreton Street, Pontypool (Moreton Street no longer exists), so Mary moved in and George continued to ply his trade as a stone mason.”
... in 1841 a Jane BEESE 40 occ Charwoman with children in household of Sar 20 Ann 8 Jane 6 all daughters, are at Downend, Mangotsfield, I have located elsewhere in Downend Charles & Sophia working away from home, living next door is a Chas Cambridge 46 occ Stone Mason so it looks like Jane "took the name" Cambridge but possibly did not marry Charles.
It may be probable that Jane never married Henry's father Chas/Charles...
In 1851 there is no Jane (about 16) anymore. Where did she disappear? Ann was 18, so she may have left her home to get married. The 1841 Jane Bees and the 1851 Jane Cambridge may not have been the same person. Also the age doesn't match.