Yes and no.
To comply with Australian regulations all you need is a bridging exam. This encompasses the whole Aussie theory but a JAR ATPL guy should be up to speed with most of it other than Flight Planning and some of the finer points in met.
However, if your Australian ATPL was obtained purely by working the loopholes then you may be scuppered. A genuine guy with a fair ol' time flying in the UK on eg 737s or A320 etc having gone through the full JAR ATPL bollox may viewed upon favourably.
NOTE!!! I am not a recruiter so my comments are to be taken as a guide, not gospell.
Good luck.