I used Airline Transition Consultants and AeroCrew Solutions. ATC were quite expensive but I will say they do a very thorough job and their consultant spent hours and hours on the phone going through every minute detail. They really put in a lot of time for the money. I felt really good about my application after ATC looked at it and I was surprised when I didn't get the call. I will say I did not follow all of their advice and used some of my own judgement where necessary.

I'd made some changes and additions after ATC looked at it and I wanted another set of professional eyes to double and triple check it again. That is when I used AeroCrew Solutions for the second time. They found one phone number that wasn't the same format as the rest and the issue with the addendum I mentioned.

One thing I didn't mention in my original post is that I used Ready Set Takeoff (RST) for technical and cognitive prep. RST was absolutely essential in my success. Don't underestimate the networking and peer knowledge available on the RST site from prior interviewees. My advice would be to join RST before you get the invite.

I spent a fair bit of cash all in but I'm not sure I'd be sitting where I am if I did not.

Airfix