Now I had thought that I had found his birth in Lambeth (Mmn Gray) which matched up with a family of cabinet makers.
I do believe this is the correct Charles, and you are being thrown off by the 1911 census.
When Charles Dennis married Annie Elizabeth Webb in 1866 it was at St James Shoreditch. He was living a 5 minute walk from the church in New Inn Yard, Hackney.
Witnesses at wedding were Henry Webb and Ann Webb. Charles signed his name.
IN the 1851 census George DENNIS cabinet maker with wife Elizabeth (nee Gray) and family living in Southwark St George.
The son Charles is 6 born in Southwark. His birth registration is Dec ¼ 1844 Lambeth.
In 1861 that same son Charles is working as a shoeblack and boarding (still in Southwark), with the “Superintendent of Shoe Blacks”. (I note he married the daughter of someone in the shoe business)
In the 1861 census George Dennis is still in the Southwark area working as a cabinet maker, along with a couple of his oldest sons in the same trade.
By 1871 census the father George has died (possible death 1865 St George Southwark, age 58) and the rest of Dennis family is now living in Somers Town, St Pancras – older sons doing the cabinet making.
In 1871 your Charles is also in Somers Town, St Pancras (close to the rest of the Dennis family).
One other thing to note - Charles's siblings who were also born in the Southwark area, say they were born Middlesex and St Pancras / Camden from 1871 & in later census.