Neil, Since orchids do not have branches to the plants, they are not pruned for height, only to divide clumps, but you don't need to do that. Keep the plant in good light. I realize your sunlight intensity is lower than ours, but here, they cannot take direct sun in the warmer months when they're outside because it will burn the leaves. Your local orchid society probably has advice on whether or not they can take direct sunlight through a window in the winter. If you hold your hand about a foot above it, you should be able to see a shadow cast on the leaves. Like Ralph said, it looks very healthy and should not have problems standing straight as long as it gets enough light and the potting medium is in good shape and able to support the plant. Often orchids are held in place with large V-shaped or U-shaped wire pins that are pushed down into the potting medium to hold it tightly over the roots. When the plant throws a bloom spike, you could see if that needed a small stake. That is a beautiful container. The pot with the orchid lifts out, right? I can see a root extending over the edge of the pot. When you see more of those climbing out, it will be time to put it in a wider pot.
Ralph, with your climate, you can keep Cymbidiums outside most of the year since the are cool region orchids, right? In Georgia it was so warm in the summer that the plants had to be watered & misted with chilled water to make them happy enough to bloom and in the winter, they needed a cooler greenhouse than the other orchids.