Can't see any commercial success in this. To justify the costs of the operation it would need a high business travel ratio and high yield, Perth just has not got that market. Nonstop through to Sydney, if possible (I believe not) and you might get adequate revenue, but not Perth. It would be pointless relying on connecting traffic to Melbourne or Sydney as they have much better existing one-stop links with London.
Major business in Perth is basically some mining, some oil/gas exploration. London, a dominant point for finance and media, is not a centre for either (Vancouver or Houston might be better).