Do a little bit of a search on this thread, I discussed this a while back when weighing up what boots to get. Basically there are 3 (at least) C&J's chukka type boots, the Tetbury (which is the most formal and sleek model), the Chiltern (which is more casual and rounded) and the Chukka which is somewhere in the middle, has a leather soul and is unlined.
I have the Chukka model and I love it (was just saying today how great it is). In terms of sizing I take a 9.5 UK in most shoes, including Church's consul and C&J Sydney. However I slightly wide feet so with the Chukka sized up to a 10 UK as it on a narrow last. I also wear a 10 UK G in church's Last 73. That said I think I could get away with the 9.5 UK too but am very happy with the 10 UK.
I know Mr Nice Guy (Gerry Nelson) has the Tetbury in a 9.5 UK and it fits him well and we share a similar shoe size (and good taste in clothing). Some other members have the Loake Pimilco which is very similar too.
If I was to get another pair I might look at these from Carmina, which are about the same price -
As thebrownman said, if you are in Melbourne, you could try them on (and from my understanding get a good price) at Double Monk, but I am not sure which models they have or that you are after.
The other option is to join a number of us here in waiting for the release of Christian Kimber Footwear. I have seen his prototype models for the desert boots/chukkas and plan to buy a pair when they are available (next few weeks I believe).
Hope that helps. i would definitely recommend a nice pair of dark brown suede chukka boots.