tried and failed to change Alfresco port in Bitnami VM

In some of my initial attempts, working with Bitnami's Alfresco VM, I tried a few ways to change the port and failed. Just documenting what does not work - 

https://docs.alfresco.com/4.2/tasks/share-change-port.html

mentions changing the <web-extension>/share-config-custom.xml file, not just in alfresco-global.properties -

https://docs.alfresco.com/4.2/concepts/share-configuration-files.html

The path above is tomcat/shared/classes/alfresco/web-extension/share-config-custom.xml

But probably these docs assume that Tomcat is already configured to run on the fresh port, and that is probably why just doing the above failed for me.

And finding the location of the Apache configuration files on this Bitnami VM which were doing the proxypass from port 8080 to port 80 - 

/opt/bitnami/apache2/conf/bitnami/bitnami.conf
had a line 

Include /opt/bitnami/apache2/conf/bitnami/bitnami-apps-prefix.conf

bitnami/bitnami-apps-prefix.conf has

Include /opt/bitnami/apps/alfresco/conf/httpd-prefix.conf

httpd-prefix.conf has

Include "/opt/bitnami/apps/alfresco/conf/banner.conf"

Include /opt/bitnami/apps/alfresco/conf/httpd-app.conf

and finally 

/opt/bitnami/apps/alfresco/conf/httpd-app.conf

has the proxypass lines for alfresco and share, like

<Location /alfresco>
ProxyPass ajp://localhost:8009/alfresco etc.