I am answering this on the message board, rather than contacting you direct, in case other people duplicate the areas we are trying to help you with.

You cannot rely on the 1886 birth in Warwickshire, being the correct one. This is a death:-

John William Chamberlain born abt 1886 died 1905 Bromyard Herefordshire, Hereford and Worcester, Worcestershire

This does not prove that it is the same John William Chamberlain, but it shows the need to check. You really need the marriage certificate of this man. From that you will find the name of parents of the bride and groom, and possibly be able to match them on an earlier census, which would show you the place of birth and an age. His age may also be on the marriage certificate, but it may just say that he was of full age, meaning he was at least 21 years old.