Here is the VHOST config. I just changed the NameVirtualHost param to add the port 80. Got rid of the warnings but same result with the redirect.

# Include the virtual host configurations:

# DocumentRoot /var/www/sitaracoza
# DocumentRoot /var/www/sitaracoza
NameVirtualHost *:80
#Include /etc/apache2/sites-enabled/[^.#]*
# DocumentRoot /var/www/sitaracoza
<VirtualHost *:80> 
DocumentRoot /var/www/sitaracoza
ServerName www.sitara.co.za

# Other directives here

</VirtualHost>

<VirtualHost *:80>
DocumentRoot /var/www/reservations
ServerName reservations.sitara.co.za

# Other directives here

</VirtualHost>
ServerName www.sitara.co.za

Here is the output from apache2 -S

 apache2 -S
VirtualHost configuration:
wildcard NameVirtualHosts and _default_ servers:
*:80                   is a NameVirtualHost
         default server www.sitara.co.za (/etc/apache2/apache2.conf:399)
         port 80 namevhost www.sitara.co.za (/etc/apache2/apache2.conf:399)
         port 80 namevhost reservations.sitara.co.za (/etc/apache2/apache2.conf:407)
Syntax OK