Canberra (note initial capital letter)
I'd be surprised if we got immediate pensions at 20 years. My information is that the Treasury are VERY anti any permanent immediate (rather that preserved) pensions before a "normal" retirement age. They wanted 40 years (!!!!) and the services were indeed pressing for 20 as a compromise between the 38/16 and the 22.
There seem to be a number of new things coming out around the 30 years service mark, so may be that'll be the compromise.
And perhaps we'll also get around the "officers' pensionsable service doesn't start until age 21" nonsense. And then there's the pensionability of flying pay ...............................