MANY Bangkok restaurateurs have got the idea into their heads that bigger means better. It all started a few years ago with a crop of restaurants seating many hundreds. They became very successful and fostered greater ambitions. Seating for hundreds gave way to seating for thousands. The inflation in restaurant size seemed to have reached its apex with the establishment of the Tamnak Thai Restaurant, famous for its trademark roller skating waiters and waitresses. For a couple of years it held the record for the world's largest restaurant, accommodating some 3,000 diners at a single sitting. However, the owners of Tamnak Thai soon got itchy feet and decided to trump themselves with a 5,000-seater restaurant, called Mang Gorn Luang, or the Royal Dragon. Occupying a 32,000 square metre site, the restaurant quickly secured its place in the Guinness Book of Records as the world's largest restaurant. The Royal Dragon is truly a festival of excess. Subtlety is not the order of the day. The colours are bright, the mandarin style uniforms of the serving staff are gaudy in the extreme and the entertainment is hardly suitable for candle-lit dinners to theaccompaniment of Vivaldi's Four Seasons. Here entertainment is modelled on the style perfected in Las Vegas, where spotlights blaze at full intensity and amplifiers are turned to maximum volume. Alongside the standard, and wholly predictable ''Thai cultural show'' is a wonderfully kitsch display of aerial transportation - with heavily made-up male and female artistes whizzing through the open-air restaurant on firmly secured cables to the accompaniment of clashing cymbals. Talking to the restaurant's amiable managers is akin to a conversation with a production manager on a car assembly line. They trot out figures like seasoned veterans. Here's a sample: The restaurant has 10 kitchens, 1,000 staff - including 300 cooks, it orders 100 kg of rice per day, and up to 100 kg of lobsters every two days. The list of dazzling statistics seems endless. Back at control centre - there is indeed such a place - computers whirl as they process the orders, taken by the roller-skating waiting staff, and convey them to the kitchens. The efficient control of the system is designed so that each order should take no more than 10 minutes to arrive on the table. Backing up the computer system is a fleet of floor managers armed with walkie-talkies enabling them to follow up on delayed orders. What about the food? This is, after all, a restaurant. Well, like the restaurant, the menu is huge, covering Thai, Chinese and even a small section of European food. The emphasis is on seafood which is very fresh. Catering on this scale leaves little scope for originality so the Royal Dragon sticks with well established dishes which are likely to be familiar to most patrons. The food is fine, not spectacular, not particularly tasty but certainly edible. However visitors to the restaurant must be coming more for the spectacle than the food. They will not be disappointed. Prices are very reasonable for overseas visitors, but on the high side by local standards. A meal, including, for example, a Thai soup, steamed fish, curry crab, prawns, Thai hors d'oeuvres, chicken, vegetables, fried rice and fruit or Thai desert, and a soft drink or beer, should total no more than 300 baht (about HK$100) per person. The Royal Dragon sounds like a tourist trap but is not. In fact 80 per cent of the customers are locals. Thais love spectacle and they get their money's worth here. As for visitors, they should pocket their inhibitions and head for the outskirts of Bangkok in search of the Royal Dragon just for the sheer hell of it. The Royal Dragon is located on the Trad Expressway, kilometre 1, at the Base of Bang, Tel 398-0037-43 for reservations. It is open for lunch and dinner.