Can you please tell me more about the Barker tree who are related to Louisa?
They are unlikely to find any close Corkill relatives of Louisa in NZ because she was the only one of her family who went there. Her brothers emigrated to the US and to Africa (and then England), and her sisters stayed in the IoM.

Her father John's parents were not John Thomas Corkill & Elizabeth Caine (censuses and wills) - their son was a different John.

I think you would need more than a lifetime to sort out all the Corkill families, because they didn't stick to any particular parish, and there were so many. I have worked out a few, but mainly originating in Maughold.

Sue