Thanks, all my other 3rd parties were where I expected (bottom of the list) but this one was AWOL.
The software company came back and told me to "Please restart the computer, launch Logic and "Reset & Rescan Selection" for the plugin in Logic's Plug-in Manager to validate." and then the magic happened. Interestingly, the tick box to use it was not ticked. I ticked it, reset them all and the magic happened. Thanks (as usual) everyone for your input.