Hello Alan,
It's good to hear off another member of the Crennell clan,if you could tell me the names of your Grand parents I will be able to tell you if we have a close link.I have found two Alfred Crennells in my side of the family,so one of these could well be your father.
I would be interested in seeing your brothers report when it is finished,if I can be of any help let me know.
Take care,
John Kelly mother nee Crennell.