A dinner of champagne, caviar and smoked salmon at up-market department store Harrods was how Hilda Garcia, a Mexican anti-corruption official, spent part of her $450 per day travel allowance in London last year. A colleague, Jorge Pulido, sent to Kuala Lumpur for a conference, managed to spend more on taxis and meals out during a layover in Frankfurt than he did on his six-day hotel stay in Malaysia. Jaime Cerdio was more austere. On a trip to W…