Hi Carol,
Thank you for the information!
I have found one Robert Wells registered in 1927 (in Sept) without the middle name of William. This is the only record that's fits, especially based on the information you've provided of the 42 day time limit to register a birth.
The record shows a Robert Wells was registered in Mildenhall with his mother's maiden name listed as 'Stebbeds' - I am now following this possibility up.
Thank you again :)