Probably easier to just get yourself 175 hours, and do the JAR stuff when you get to the UK. Only worth getting the Aus CPL if you plan to work in Aus, otherwise you will have to redo a lot of it, and there are a LOT of differences (I converted CAA CPL to Aus CPL years ago). The theory is much harder in the UK, the flying standards easier than Aus, the weather and procedures very different.