Load factor performance on a new route can be misleading depending on how many sale fares were released to stimulate the new route, and what periods of travel these fares existed for. If these numbers exclude deeply discounted fares, and they're pricing at a premium (due to the benefit of this route), then this is a good result considering there are a few options ex Perth to London, be it an extra stop for all pax excluding Perth pax.
It would be better to see the rASK performance on this market.