I have just noticed that if you do a google search:
ultrasonic anemometer construction
This page comes up on the first page of the google search.
I dont know how long this has been occuring but it also has the quote:
I believe that this is the only ultrasonic anemometer on the web which has
enough detail to enable it’s actual construction.
I'm still waiting to be proved wrong.
I would not be upset if proved wrong, but it would mean that I would have to improve my search technique.