There are certain varieties of this that can only be propogated from cuttings Paul, possibly you have one of them?

If you actually had the berries, Paul--rather than the spruce-cone-like heads the seedless kinds produce--the first thing to do is to remove every last trace of fruit from the seed, and scarify the seeds a little. They are adapted to go through a bird's digestive tract before sprouting. Once the seed is prepared, sow it on any good, moist seed starting mix, and cover it with about 30 mm of sand. Apply bottom heat to keep the soil about 30º C to 33º C. The seedlings will need ample sunlight from the instant they sprout, so give them very bright artificial light if you can't give them direct sun.

Modern Lantana varieties are complex hybrids, so the seedlings will be completely unpredictable in flower color and plant form.

Sorry, Paul! That's 3 mm of sand, not 30! Oooopps!