The RNHF have the three Stringbags as they each represent the different variants that served with the Fleet Air Arm; the Mk.I (W5856) II (LS326) and III (NF389).
They do of course have a Sea Fury and Sea Hawk, though both under repair at the moment.
In the 1980's The Royal Navy had a few Gannets in store for possible use with the RNHF, as well as a Harvard.
Unfortunately when the Navy pulled out of financing the Flight they had to be sold to raise much needed finance.
In fact XT752, the Gannet up for sale in the US was one of those aircraft.