A probably fake photo from 1974 of HMS Tartar's trip there. 'A sentry-box was constructed on Hall's Ledge, with two marines in full ceremonial uniform posted alongside, and the Union Flag was hoisted above.'
Every now and again Britain lands some people on this lump and takes a photo to prove it is theres. 'Former SAS member and survival expert Tom McClean lived on the island from 26 May 1985 to 4 July 1985 to affirm the UK's claim to the island'. Waves roll over the island so he had to hide in a bolted down giant coffin for the duration.
They do this partly because owning the Falklands isn't grim enough for them. And partly for all the oil and gas and such that might be between Rockall and Ireland.