Hi Sarah, yes indeed it sounds like we're looking at the same line. As I say, I haven't really researched anything myself that far back, what I have is only what I've gathered from other trees on Ancestry, so it's by no means to be trusted as accurate until we can double check it for ourselves. But I will invite you to my tree as in any case it makes sense to join forces when we're researching the same line. I'm originally from Devon myself, like the Blacklers themselves, although these days I'm in Germany (and hence relying on sources here rather than getting a chance to go to the Devon record office and do some real research!).
Best wishes and no doubt we'll be in touch further. Tree invitation on the way now.
Marcus