Hi Richard,
Thanks for purchasing the plugins and sorry for the trouble!
A missing license tab is often the result of running different versions of The Events Calendar with the premium add-ons. Are you able to go to your Plugins page and confirm that both The Events Calendar and the premium plugins are running the same version (e.g. 4.1)?
You can also head to Events > Settings > Help, copy your system information and paste it here as a private reply and I’d be happy to check for you.
Thanks!
Geoff