Check that the jelly is set. If so, proceed with this step. If not, chill until completely set.
Loosen the jelly from the bowl using a knife, flexible spatula, or any implement that won't damage the jelly too much. Then invert the bowl over the centre of the cake. The jelly will probably be somewhat reluctant, but with a few taps on the bottom of the bowl it should come out. Et voila! A smashing orangey bit!