Norton Mobile Security - are there 2 versions?

My phone came with a free trial of Norton Mobile Security. When the trial was up, I could pay $30 pa for a subscription. But then I went to a mobile phone kiosk which sold me a cheaper version for $6 for 2 years. This app looks different from the original. It generates another app called Norton Anti-Theft.

I uninstalled the original, but it keeps coming back, saying there is an update available. This one is on the Google Play store and is called Norton Mobile Security Lite. This link might show it: https://play.google.com/store/apps/details?id=com.symantec.mobilesecurity  and https://mobilesecurity.norton.com/ I just looked in Google Play on my computer and it says it is installed. But I had uninstalled it. Is this why it keeps coming back? Further down in the notes on my phone it says in app purchases of $29.99, which is what you pay after a 30 day trial.

The one I have installed at present, for $6, was not available through Google Play Store. You had to (temporarily) tick the unknown sources box in Security.

Is the $6 version dodgy, or is it genuine?

Thanks

John