My guess, based on the following:

Charles Clague was in the Radcliffe household in 1841, along with dau Elizabeth Radcliffe.
The only possible bapt [if he was baptised] was illegitimate son of Eliz Radcliffe, no father given.
James Radcliffe, head of 1841 household, died in 1848.

There was no Charles Radcliffe of the right age in later censuses. Only Charles Clague.

Presumably only one Charles Clague of that age in censuses [but I don't have all Clague entries].
In 1851 he [if the same Charles] was in the household of Edward Clague and his wife Elizabeth Quayle, but said born Lezayre.
No bapt.

In 1881 there is only one possible Charles Clague, living in Lezayre but born Andreas - so this looks like the same person.

Could he have gone to live with his father and father's wife in Lezayre between 1841 & 1851 when he had to leave the Radcliffe household, for whatever reason? James Radcliffe, Elizabeth's father, died in 1848. Dau Eliz Radcliffe the possible mother died/ got married?

Sue