It is well worth a visit. You can also see HMS Alliance (guided tours from retired submariners) and the captain’s cabin from HMS Conqueror (the only nuclear submarine ever known to have engaged and sunk an enemy warship, the General Belgrano).
HMS Alliance is a much more modern submarine. Diesel-electric launched in 1947. A large number were ordered for the Pacific war but were not required for service. She was extensively refitted in the late 50’s for silent running. She was in service until 1973 and a training ship until 1979. She is now a museum and memorial vessel. I will post a picture of Alliance when I can.