I apologize for being the bearer of bad news, but the UK's Adoption
Act states that an adoption order may not be made for "a person who
is, or has been, married or who has attained the age of 19."
From the UK Adoption and Children Act 2002:
"Section 47: Conditions for making adoption orders...
143. An adoption order may not be made in relation to a person who
is, or has been, married or who has attained the age of 19"
Adoption and Children Act 2002, 2002 Chapter 38, hosted by
Her Majesty's Stationery Office
"To be eligible for adoption the child must be under the age of 18
years... Should the child be married or has been married he cannot be
UK Department of Health: Adoption
"If the child is over 18, and is or has been married, he or she cannot
"To be adopted a child must be under 18 and never have been married."
This information would appear to be rather definitive. Of course,
Google Answers is for informational purposes only, and it should not
be considered a substitute for the professional legal advice of your
search terms: "be adopted", "over 18", britain, uk, adoption
Again, I'm sorry if this isn't the answer for which you were hoping.
And, of course, nothing in the world can stop your husband from being
the "grandfather" in an unofficial, but no less worthy, way. Thanks.