The Adoption and Children Act 2002 gave unmarried couples including same sex couples, the right to adopt. This became law in December 2005.
A same sex couple does not need to be married or in a Civil Partnership in order to adopt. You will just need to show that you are living together in a committed relationship.
Adoptions by LGBTQ+ Adopters are on the increase and according to the department for education for the year 2018 to 2019, 1 in 7 adoptions were by LGBTQ+ Adopters.