Las Cadenas was a restaurant.
Las Cadenas was owned by a friend of Oscar Botcherby, who was managing the restaurant with the help of his girlfriend Anita in 1985. The Second Doctor (who had been temporarily transformed into an Androgum) and Shockeye ordered a massive meal at the restaurant, running up a bill of 81,600 pesetas. Oscar refused to accept the twenty narg note which Shockeye offered as payment. Shockeye stabbed him to death in retaliation. (TV: The Two Doctors)
Behind the scenes
Though not referred to on-screen, "Las Cadenas" translates to "The Chains".