Anyone know approx cost and can recommend a method of shipping a sail from a shop in the UK to Aus?

don't know about sail prices, however I recently had freighted over a rear bumper cover for the car. The package was only about 1.8m long x 250 x 200, weighed less than 3 kg, cost GBP45

there are two labels on the box, one is from parcel2go and the other from www.dpd.co.uk, so perhaps either might be able to give an online quote.
The sail length will probably mean Royal Mail wont freight it, the other alternative is good ol DHL. DHL can be well priced if the account holder uses them a lot, or they can be very pricey!!

nigel