Should I respond?

Yes I have. But I was not in a receptive mood and I've largely forgotten it.

Putting things off to read later is one of my defences. I never read any kind of letter if I'm feeling vulnerable, and in extreme cases I'll ask my wife to read it first. (As I did with Madame T's referral.)

One whammy at a time, please!

You don't have to do it straight away. This is not an emergency. Give yourself time to calm down first.

I wouldn't respond. If she wanted to know, she could have sent it registered mail. It could have ramifications down the line. If she cared how you felt, she would try to connect with you. I wonder if she's asking you to act in ways that are difficult, for her comfort and protection, not yours. I don't think I would do it. But I'm pretty angry at my former T right now anyway.

having said that, if I read the letter and felt heard and understanding, and was no longer angry, I might respond. But I doubt I would read the letter immediately. And I don't think you are under an obligation to read the letter.

of course, if you don't respond, she could send another letter, RR.

I think she's put you in a lousy and difficult position.

Depending on what else happened, and how understood (not) I felt, I might tell her that I received her letter and was passing it on to the licensing agency. I don't think terminating by letter is a good thing.