Looks like were off to Perth in October via Singapore and the BA website states:-
Australia’s Quarantine
Aircraft entering Australia and New Zealand require to be sprayed twice initially with Permethrin residual insecticide, and secondly with a Phenothrin spray.
We have the Phenothrin but does anyone know where we can get the Permethrin and also how do the regulations get applied in practice, i.e. do you show the empty cans or is there specific paperwork to be completed??
Many thanks.