I should have added that the Will for William (& Margaret) Cavendish that I have a copy of is indexed as:

CAVENDISH, William 1811 Dgs A 19 0106238

but there is also:

CORJEAGE, William 1811 Bra E 1 0106414

Which I have not seen. I cannot say for sure who this is - his son, born 1786, perhaps? If it is, there are 2 burials I can't find! If it's another Will for William Cavendish, filed under the name he was baptized and married with, then I'm ignorant of why this should be, or if it would be unusual to have one will in the Archdeacon register and one in the Episcopal register in the same year.

Can only guess until I get to see it, I suppose, but what I'm getting at is that he could be buried under either name.