You can't just change the port because that will disable the Tomcat application listening on port 80. The idea is that a browser going to port 80 gets the Tomcat app and a browser going to 8081 get my fabulous web pages.
I think I solved it by installing a complete separate instance of Apache.
Very clear istruction on how to do this are at
This allows a completely different set of configurations and web page directories. You can also run the second sever as a different user than apache and keep everthing nice and separate from the other server. I installed and it serves the web page on port 8081 will Tomcat is seen on 80.
I am held up getting the cgi to work as is sometimes the way with initial Apache configs. I suddenly got all these other jobs to get done so this project is parked for a few days. However I am sure it will work.
Anyway thanks for your suggestions.