There's only two docks in the UK that will take the carriers: Rosyth and Port Glasgow. The latter is privately owned and barely sees a vessel from one year to the next, in the five years I worked on the Clyde I saw two use the dock, both vessels were cable layers.
Getting into Rosyth on one shaft would be interesting as the river basin would have to be negotiated first in order to line up for the dock. Commercial tug companies name your price!