Ah did a little googling myself. No expert. But for anyone else wondering.

Both is the answer

The first positive consistent fusion was achieved in 2022. So over COVID. I may have missed it due to hiding ;)

But yes this is experimental. But fully expected to be the first full scale power plant. So Def worth the UK gaining the experience and solving the issues.

It is not expected till 2040. So 2.5b is way less over 15 years then it seemed.