I tried this and the returned page was bool(true).
I've redone the application on a different server with much the same result. The second insert record did send 2 emails, but since then I have received none. The Client is the first email address on the list, and that one is possibly going through, but none of the others has arrived. Two are direct email addresses, one is the email address from a field. I've tried changing the order in case one is failing. I'm still not entirely certain the client's email is going through, although I hope so.
I used this extension for another client, and when I got the test emails I assumed it was fine. However I'm now very worried that he hasn't been getting his emails either.