I have been researching "Aver" in Cornwall for a number of years now. I had very little sucess until I found "Online Parish Clerk Cornwall".
There are births, deaths & marriages available from this site.
My g g grandmother was Elizabeth Aver, she married James Angove 18 March 1835 in Kenwyn, Cornwall. I found their marriage but still have not found their births or her death. Though I have found most of Jane's immediate family her parents marriage and their deaths, plus the births of five of her sibblings and the marriages of six out of the seven of them.