Looking for Cox S IN England

I have been researching my family in England..The Cox's. My greatgrandparents Francis and Irene) came from England in 1928 with their 2 young children (my grandpa Orlando and Aunt Hazel). I have found out quite a bit of the history with alot of digging but what I have not found is the graves for Francis' parents...John Thomas and Bessie Cox. I think they possibly were buried in Turo Cornwall but am not sure. John Thomas's dad and mom were Francis Henry Cox and Sarah Lucritia (sp) Nile.