MORE THAN one hundred different models of British-made cars, representing 23 different British manufacturers, served as a real eye-opener to the thousands of motor-conscious Americans who jammed the automotive show at New York City’s Grand Central Palace, April 15 through April 23. Sir William Welsh, British representative for the British Motor Industry, stated that Great Britain’s goal is 50,000 cars a year, roughly a tenth of Britain’s present production, to be sold to the United States market. That this goal can be reached in 1950 is highly dubious as it would mean quadrupling the British 1949 sales record. But, with the presentation of such large or sleek awe-creators as the Jaguar, Aston Martin, Frazer-Nash, Bentley, Bristol and Rolls Royce, to mention a few, or the lesser-priced sports-styled jobs, such as…