Are you talking about an indoor plant, Lambton? That used to be called Heptapleurum and is now called Schefflera? If you are , I can tell you exactly what to do, because I have one too and am always cutting it back and rooting new plants. If that is the plant you mean, wait till late Feb/early March (f you can bear to) , cut back as much as you want. Take the tops you've cut off, shorten them to about 8/10 inches, remove the lower leaves, pop them into water (I use an old drinks bottle, helps keep the stems from dropping or leaning too much). Stick on a window sill and wait - should be about 6-8 weeks, but keep the water topped up and check regularly - when the roots appear, pot the cuttings up.