Hi 99,
My usual advice is that if you are deciding between flying and another career, chose the other one!! If you don't have anything else you might want to do- welcome aboard!!
It certainly would be a perfectly viable alternative to stick at what you're doing, get your PPL, then buy a share in a Pitts or a glider and embark on a very enjoyable and satisfying path as a part-time flyer.
If, however, you are set on flying as a career, there are a couple of holes in your plan.
Firstly, £30 000 is probably NOT going to get you into a jet. These days, on top of your frozen ATPL, you need either to do a few years/000 hrs in a secondary type of flying (regional turbo-prop, freight, air taxi etc) to get on as a DEP, or else sign up for one of the self-sponsored type schemes to get a type rating and employment with a European jet operator.
After that NO amount of FO time is going to get you a job with a an Australian Jet operator. They have all the guys clocking up thousands of hours command in 402s/Metros/Saabs etc. to choose from. If you are coming to Aus, either come with a good amount of Command time (e.g, STAY with the Air taxi or freight company until you've had a command for a while) or come with the expectation of spending a good amount of time in the Bush (andbe warned, the Ozzy outback can be a VERY hard place for women to live, so have an honest appraisal of how your wife will cope.)
As an idea, could you follow your current professtion in Australia? Alternatley, could you save sufficiently to move and train full time in Aus? It will be a MUCH cheaper exersize to get a CPL with ATPL theory in Australia, you'll have the relevant Australian licenses, and have a chance to make contacts and get a feel for the industry there. Plus you'll have a chance to do the Ozzy bush thing which, whilst challenging, has left all of us who've done it with memories and experience we will cherish forever.
In summary, it's easier to transplant an Aussie pilot to Europe (ask me how I know!!) than visa-versa. My reccomendation would to either train and plan to stay in Europe, or do the whole thing in Australia.
As to the "is it worth it" bit? Well, it's all I've ever wanted to do and I feel very proud to be doing what I do for a living. It can be frustrating, boring, tiring and heartbreaking, but i still have a chuckle to myself when I think about the fact they pay me to fly that big, shiny jet.