My fiancé has a 6yr old who stays with us, as his mother is deceased. Over a year ago he started to call me mummy. Me and my partner have spoke about me adopting him and would like some advice on how to go about it

Yes, you and your fiancé hire an attorney, it should not be that hard.

Completely agree with Fr_Chuck. This should be fairly straight-forward. Getting an attorney is your next step. Congratulations on your new family! Cathy