Hi,
I'm not sure how much you know about the family, but I've tracked a bit about them, although there are one or two gaps. Charles Henry Clavey, your g. grandfather was born in East Harptree in 1894 (baptised there 1895) and he married Caroline Beatrice Payne on March 27th 1916 according to his war record. If you haven't seen the war record, I'll send you more details. He had several more siblings than those you mention, including a boy named Redvers, born in 1901 (shades of the Boer War hero!).
His parents were Richard (Ford) Clavey and Louisa Moon, married in Bedminster registration district in the March q. 1873 (ref 5c 1038) with his surname spelt CLEVEY. Louisa is presumably the child baptised at West Harptree in 1851, dau. of James and Jane. I expect you have seen Richard in 1871 in Wales with a cousin of some sort? Beyond that it's a bit of guesswork as I can see Richard with his parents, James and Caroline in early Census' but I can't find a marriage for them anywhere (parish register or FreeBMD). I think James must be the son of James and Martha who was baptised in Chewton on August 20th, 1820, and Caroline (if she is Caroline Ford as I suspect) could be the one baptised in Chewton on September 15th, 1823, dau. of James and Fanny. Without a marriage certificate for James and Caroline we can't be sure, but it is true they both claimed to have been born in Chewton. Several of the baptisms of the children are in the registers and it is possible to go back further with these lines if you want.
Do you have access to Ancestry? it is often available in libraries foc. and this would give you a chance to see the register entries and follow the families back if you wish,
Steve