Premium to the Caribbean??

Hi everyone,
I've been reading this lovely forum for many years and it's been so helpful, having planned our last few years of holidays around Virgin routes!
Anyway, we're looking at next year's holiday and are hoping to go to the Caribbean during the school Easter holidays (any time between 6th April and returning 22nd April 2019), either Barbados or Antigua. I was hoping to fly Premium but I'm not seeing any availability at all past the end of March 2019 on either route. I've looked at straight cash options as well as using miles and there's still nothing other than Economy or Upper. Am I looking to early (or too late!) or are there really no Premium seats to the Caribbean in April next year?!
Virgin Holidays doesn't have the option of upgrading to Premium either so I haven't got a clue what's going on! Have I missed something?
Many thanks for your help!
I've been reading this lovely forum for many years and it's been so helpful, having planned our last few years of holidays around Virgin routes!
Anyway, we're looking at next year's holiday and are hoping to go to the Caribbean during the school Easter holidays (any time between 6th April and returning 22nd April 2019), either Barbados or Antigua. I was hoping to fly Premium but I'm not seeing any availability at all past the end of March 2019 on either route. I've looked at straight cash options as well as using miles and there's still nothing other than Economy or Upper. Am I looking to early (or too late!) or are there really no Premium seats to the Caribbean in April next year?!
Virgin Holidays doesn't have the option of upgrading to Premium either so I haven't got a clue what's going on! Have I missed something?
Many thanks for your help!