May 3, 1982

As it moves from gawky adolescence to mature middle age, the international lending community is encountering some of its roughest going. For one thing, lending to countries, which has been one of the banks' favorite kinds of international business, has become far more uncertain after the problems in Poland, Rumania and now Argentina. Perhaps more important, the margins between the interest rates charged on international loans and the rates that must be paid on deposits have remained stubbornly narrow and, despite widespread predictions to the contrary, have shown only the faintest signs of improving. ''Nobody actively involved in the market can really be happy with the existing level of profitability,'' said M.C. Deverell, divisional general manager at Barclays Bank International. ''And yet, paradoxically, the plain fact is that we would have been talking or thinking in exactly the same vein at almost any time in the last decade.''

The United States and 10 European countries agreed yesterday to establish a new fare structure for North Atlantic routes that allows airlines more freedom in raising or lowering plane fares. The multilateral agreement, initialed in Washington by representatives of the 11 countries, will be formally signed later. It guarantees governmental approval of fare changes within certain agreed-upon zones, effective July 1. ''The agreement puts into the marketplace a much more competitive structure with not nearly as much government involvement,'' said Darrell M. Trent, Deputy Secretary of Transportation, who headed the American delegation at the talks.

An article April 22 about hearings in Washington on videotaping incorrect- ly described the testimony of the actor Charlton Heston. He said he supported a special royalty fee on the manufac- turers of home videotape recorders.

''The world should understand that the people of El Salvador are not cannon fodder for any appetite, for any dictator or for any cold war.'' - Alvaro Alfredo Magana Borja, the provisional President of El Salvador. (A10:1.)

If Harrods is an institution, it is often said here, then Liberty is a monument. But while that description of this city's other large department store may befit its splendid mock Tudor facade and high-priced gentility, it is not always the best way for a retailer to sell goods. Tourists ''just come in here as though it was the Tower of London,'' David Pike remarked ruefully upon his appointment last year as chairman of Liberty & Company. ''They don't buy.''