The London Stock Exchange had a better day.

The market’s new electronic dealing systems worked better on Tuesday after the disastrous start-up snarls on “Big Bang” day, but Day Two still wasn’t perfect. Brokerage houses complained on the second day of deregulated trading that the new on-screen automated quotations of the London Stock Exchange mislaid the prices of some securities. The exchange’s reporting system, TOPIC, had fewer problems than it did on Monday when it crashed before the market opened--in front of the world’s television cameras--because subscribers were making more than 200 computer requests per second.