As to Recruitment Agencies, you need to see them for what they are and what they have to do to stay in business. They will tell you that they have the perfect job for you - they will be telling this to all of the other 20 people they are putting up for the same job. They really aren't bothered which one of you earns them the fee from the employer.
Diane makes another good point about the Regional status of Adelaide. In all other states, the capital city metro areas are exluded from migration plans and visas are only granted for 'Regional' areas. This isn't the case in SA. The SA government does not mention in the list of skills necessary exactly where those jobs are. Even nurses may find it difficult to get work in metro hospitals and this year's home grown nursing graduates are themselves failing to get work. If you want to go to Port Pirie however there is no problem.
Similarly for teaching. It is quite correct to say, as an earlier post mentioned, that the expectation was until a couple of years ago that teachers in their 50s and 60s would retire, making room for younger and migrant teachers. Two other factors need to be taken into consideration. Yes, some will retire but their permanent contracts will disappear and new jobs will be one year contracts. I also know a lot of teachers who are staying in jobs rather than moving schools because they will not be offered a permanent contract in the new role. If you want to work 200 miles from Adelaide you may have no trouble getting a teaching job.
Also you may not be aware in the UK of the fact that most Australians have to live on their Superannuation when they retire - this is usually a retirement fund that is invested to bring them a regular income they have to live on until they die. Many retirees I know have returned to work because those funds are no longer making them enough to live on and many others are contemplating working well into their 60s and 70s as they can't afford to retire. The aged pension here only kicks in when you have nothing else to live on - you do not get it automatically. So those predictions of people leaving various professions have to be tempered by the changing circumstances that now apply since the GFC.