Unfortunately camera gear can be very expensive in the UK, in part because of a 20% VAT, so a direct exchange-rate conversion of a US price is not in fact that useful to the OP.
A quick look at one online retailer I found in the UK (canon.co.uk have a list of links) shows the 16-35mm f/4 IS at £999 and the 24mm f/2.8 IS at £459, both including VAT. I have no idea whether that's good or bad, but that price for the zoom is quite a bit more expensive than the price in Australian even after adjusting for our lower VAT (the 24mm price is not).

