I have briefly revisited earth after we found our new cousins. Here are some details (some personal details have been left out to protect the innocent!)
Cousin Number One is from Australia and is my third cousin, ie we share a set of great-great-grandparents. My great grandmother Ellen was his great grandfather Joseph's brother. Joseph emigrated to Australia and it was to Joseph's house that two of my great-uncles moved shortly before WW1. Joseph and his family were very attached to the boys, as evidenced by the notices they placed in the Sydney newspapers after they were killed in action in WW1.
The best piece of information so far is that our new cousin has a diary which Joseph kept on his journey over to Australia. In it he mentions my great grandfather - we now know that he was known as "Harry" rather than "Henry". The diary also contains a newspaper clipping from a Bristol newspaper carrying the notice of my g-g-grandfather's death in 1915 - so we now know his date of death, in 1915 at the age of 83.
It's not all been one way traffic - I have sent him reams of stuff that I have - hopefully he will make sense of it all! We will definitely be keeping in touch, and of course he is now in touch with some of the other "found" cousins in Australia, so who knows, they may get to meet up.
Cousin Number Two is living in England and is another third cousin, again we share a set of great-great-grandparents, but different ones - so she is not related to Cousin Number One. Her great-grandfather was the brother of my great-grandfather, Harry, mentioned above. Not a lot of information from her as yet, but she has joined our Facebook group, so hopefully in the fullness of time we shall get to know each other better.
Still looking for more cousins - the hunt goes on!