This page
https://www.virginatlantic.com/gb/en/fl ... ights.html would certainly seem to imply all PE fares are upgradable.
Interesting that Economy Classic and Delight are the same cost to upgrade from.
One curious omission. You don't seem to be able to use miles to upgrade from Classic to Delight. I would have thought that particular upgrade would be popular with flyers whose employers have an Economy only travel policy. Perhaps VS have calculated they can sell the extra legroom seats for cash.
Finally, the upgrade price from Economy to Upper is MORE than the sum of the upgrade from Economy to Premium then Premium to Upper. I wonder why that is?
Edit:
If you’re planning to travel during our peak season, you’ll need to spend an additional 10,000 miles on top of the miles shown below for a standard season reward upgrade to Premium. If Upper Class is more your style, you’ll need 15,000 more miles to upgrade from Economy Classic or Delight to Upper Class.
It doesn't say anything about the additional cost of Premium to Upper during peak season.