The OPC is brilliant, and it helped me to unearth a few useful baptisms and so on. Your Wendron Dunstones may be linked to mine somewhere along the line, as there were quite a few families of that name in the area. The particular family I was researching proved to be quite a challenge as they bounced all over the place. My Benjamin Dunstan (the one I suspect may actually be Benjamin Dunstone John/s) went out to Australia on the 'Cressy' with his wife and several of their children in 1847, and then some of them came back to Cornwall again around mid-1851. Another daughter (my paternal 3x great grandmother) who'd remained in Cornwall, suddenly went off on a ship headed to Port Natal, South Africa (possibly she'd thought it was en route to Australia, possibly not) in 1850, and when it was wrecked on the Bar outside what is now Durban, settled down there, and married a Scots ship's carpenter who had been a crew member on the same ship, a year or two later.