Three (I think) R3 bunkers were modernised to R3A standard, which provided protected cover for the power generators and their fuel. they were Boulmer, Neatishead and Sandwich (Ash). Only the Boulmer bunker remains in use.
The R3A update provided Full NBC filtering and EMP protection, unlike the original design which was intended to give protection against a hit by conventional HE bombs.
The sheer scale of the Rotor project was staggering. I also understand there are at least three GCI bunkers in NATO that were built to R3 deign.