Richard Evan Jones married Hannah Rose Bishop Oct-Dec 1885 Wrexham district. She was nee Evans and previously married to Samuel Richardson Bishop, in 1873.
There is a Richard Evan Jones marriage in Oct-Dec 1877 in St Asaph district, to either Jane Jones or Winifred Jones, which would fit with either of those possible birth regs for David.
No children with Richard and Hannah in 1901:
https://www.ancestry.co.uk/interacti...=successSource
But their surname was just plain Jones, then. So I'm guessing that both father and son changed to different double-barrelled surnames about the same time as each other.
David isn't with Richard and Hannah in 1891 either and they have two sons, Basil and Hilary:
https://www.ancestry.co.uk/interacti...=successSource
And bother! Richard is a lodger in 1881 and David isn't with him:
https://www.ancestry.co.uk/interacti...=successSource
Not easy to find the right David on the pre-1911 censuses as we don't know exactly where he was born. There are quite a lot of David Joneses age 2 born Carmarthenshire living with grandparents on the 1881 census, for instance. But we do have a lot more info about him than when we started!