Dear Gary
I hope that you are well.
I just wanted to email you to say thank you for all your work in getting me the role at my new (Legal 500) firm. You took your time to listen to what I wanted in my career and were very proactive with making contact with the various firms, arranging interviews and responding to any queries that I had.
So far my first few weeks have been positive. Everybody has been very nice and welcoming and I really do feel like my new firm are interested in helping me develop and progress my career, which is what I wanted.
Thank you again.