Dr. Graham Peveller.
Now, he's a little older so he's kind of old school. He does ask questions about sex and your sex life and stuff. As long as you don't mind that, you should be fine.
I've heard complaints about him, but he was great with me. He even went out of his way to convince my chosen surgeon after he (the surgeon) was initially reticent about a letter from an online therapist.
He's qualified and used to practice in Britain in the traditional office setting. He's a great guy, but he's a little older, so just be patient with him (I've heard he was late a time or two to a session, but never got this myself).
Last I checked, he was good for letters in Britain, US, Canada, Phillipines (where he's at) among other places. You should check up front with him and make sure he can do it in your country.
Not sure what's expected in my area. We don't have informed consent clinics around here, so I had to see a therapist. I tried the traditional route, but the (very recommended and much celebrated) main gender therapist in my area didn't have the best 'couch-side' manner. And required additional group sessions which were mandatory and I had to pay extra for. I have a really hard time talking about trans issues in person with anyone. So, online was best for me and Dr. Peveller made me feel comfortable.
Good luck with whatever you choose.