Hey Auspomme! Under the new Team Jetstar agreement you would receive a base salary of $33,479 (rising 3% annually), and after the $11.70/block hour flying allowance, you would stand to earn anywhere between $44-47,000 over a year.
As for Australian airlines conducting recruitment drives in the UK, from my knowledge no they don't - except for Qantas LHR base of course.
I'm not sure whether a senior first aid certificate and responsible service of alcohol obtained in the UK (or the equivalent of those) would be acceptable for Jetstar or the other carriers here. If not, then if you at least show them a receipt at your recruitment day which confirms you are booked in to a course in the coming weeks then that's normally accepted.
And as for your age, forget about worrying!! Because crew of ALL ages are being recruited at Jetstar and Virgin Blue at the moment. There was a 45 year old woman in my ground school, two people aged in their early 40s in the school after me, and a man in his early 40s I spotted in the Virgin Blue ground school that was using the Qantas training facility at the same time I was there. So as long you fit the bill in their other criteria, age is not a factor!
Good luck getting in back here at home!
It's a great time to be trying, with so much recruitment going on at all 3 airlines.