Hi Maggie,
You said that his mother were reluctant to discuss??
I just have a sudden idea, right now,--what was his mother's name??
I will go to other database and see if the name match to any Allen marriages.
If we are lucky to find the marriage, I would use the parents' names and send for the birth entry in the range of years to the GRO.
They will be glad to do it as long as you have the parents' names.
How about it? I am not ready to give up on you and your friend.
This is my "last" attempt.

Kind regards,
Tees