This has to be the cheapest fares I've seen. Under a thousand pounds for business class!!
http://www.kayak.co.uk/flights/LON-P...-11/2015-11-25

Average flight price per person (includes £918.35 taxes and fees) £948.35
Outbound
Wed 11 Nov 2015

London
LGW13:35
Perth
PER17:40
20hrs 5min 1 stop
View Flight Details
Emirates EK16 / EK420
Business Class
Next day arrival


London
LGW20:25
Perth
PER01:35
21hrs 10min 1 stop
View Flight Details
Emirates EK10 / EK424
Business Class
Arrives 2 days later

Inbound
Mon 16 Nov 2015

Perth
PER05:50
London
LGW18:25
20hrs 35min 1 stop
View Flight Details
Emirates EK425 / EK9
Business Class


Perth
PER22:05
London
LGW11:50
21hrs 45min 1 stop
View Flight Details
Emirates EK421 / EK15
Business Class
Next day arrival