Yeesh.
Is Rhoda's age given on the children's birth certificates, and is it more or less consistent with an 1855 DOB?
It would be interesting to know whether hers varies as much as his (I imagine it doesn't), and if it does vary, in which directions (including when she died).
I suspect that with him being a good deal older than her, there was some attempt to minimize his age. If he did give his age accurately when they married, he was a good 9 years older than her.
Also, if it was Rhoda doing the registrations (and as you said, giving the age to the newspaper when he died), she may have been the one doing that.
I would tend to go with the earlier possible DOB, at that is what he gave on the earliest records (the later the record, the more likely the inaccuracy, in my experience), and what his death record says.
Now ... the Navestock place of birth, and name Jane Hale/s -- they come from his marriage or death certificate?
Because that seems to be the only thing that makes a connection to Essex, if I'm following. Without that, everything looks pretty Scottish?
... Not that people don't tell total porkies about where they were from. I recently tracked down the gr-grdaughter of the sister of that weird gr-grfather of mine. The sister had married a wealthy young man born in Wales whose family was from Scotland two generations earlier. Once said young man went bankrupt, he changed his name to a variant of the family's original Scottish surname, and proceeded to tell the world that he and his children were born there (the children were born in Berkshire and Cheshire). Apparently the children believed him, as the daughter gave that as her birthplace in 1901, and the son, who settled in South Africa, told the family quite a wonderful tale all about being from Scotland. So you never know -- your man might in fact have had a Scottish father, but been Essex born and bred himself.