Revived gain from EIS deferral

[ms7dcml]

Hi all, I can't find the answer to this in the forum but please forgive me if it is buried somewhere. I have a number of EIS investments (some <3 years old, some >3 years) that were purchased with deferred CGT. The deferred CGT was a mix of 20% and 28% liabilities. I know that the deferred CGT will be revived when the EIS investments are realised (with any losses on the EIS either offset against income or capital, whichever makes sense at the time) and my understanding is that the then prevailing rates for CGT would be used. If my view is that there is a reasonably imminent (in the next year or so) risk of GCT rates rising then it might make sense for me to revive these gains now. My question is whether it is possible to revive a gain immediately and also to confirm my understanding that revived gains are at the prevailing rate.
Many thanks