it is easy to see why, page-9

littlebenjipollard,
The markets certainly are an ugly critter at the moment and no one knows where they are going short to medium term.

The part on the selling is an interesting one; if I was sitting on a loss your scenario is potentially a good one. However if you are sitting on profits (as I and many long termers are/ could be) then potentially it is a risky move for marginal gain.
This will create a taxable event and tax will be due to be paid in the future. Certainly (if you are a believer in the long term) this could have negative consequences and create a cycle of selling to pay tax bills in the future. Remembering that NuPower de-merger reduced costs by around 31%. Again this is not everyone nor is it advice (I am not qualified for that).

Certainly a terrific announcement and hopefully more to come.