Anyone have experience with a lawyer who has been able to get a request for a same-sex partner(unmarried) Designated Activities Visa(or the like) approved?

I hear they're really hard to get. I want to make sure my chances are at their best.

I'm having a surprising amount of trouble finding someone who has experience successfully helping get an approved same-sex partner Designated Activities Visa, or other visa which may help us live together.

Does anyone have experience with getting one of these, have any suggestions on who to contact, or even just point me in a more specific direction to find one?

Thank you!