I inadvertently downloaded only the download that appeared when I completed my purchase. This showed only the Events Calendar Plugin. However, when I returned to my account later and checked my account section called ‘downloads’ I now saw, for the first time, the two add-ons Event Calendar Pro and Tickets. So I returned to WordPress and installed the two additional add-ons and now my licence is accepted. So all resolved, and looks good. Sorry to have bugged you.
Stan