If your GP can do it, I say ask your GP. Your mental health is part of your overall health, and IS something that falls under your GP's radar. I mean, I have some skin issues that I have seen dermatologists about, but when I get a checkup I still talk to my GP about it -- it's just not her specialty to deal with in depth.
I admit I'm really biased against your T, who has been really unreliable. Paperwork is paperwork... it just needs to get done, right? So pick someone who'll get it done.
Sorry you're still dealing with the aftermath of your exT's irresponsibility