Madasacow
I am no expert and a little out of date, but I have jumped through most of the hoops, so thought I would share some of my ideas with you. Seems pretty consistent with what's been discussed here although there are obviously some creative ideas out there.
Your service pension will remain linked to the UK inflation index and added to any Australian income and any other 'worldwide income' you may have and taxed accordingly - at Australian rates. This is not necessarily a good thing as Oz rates are quite high, rather they cut in at relatively low income levels, but there is not much you can do about this I believe.
As far as I am aware, Paymaster needs to pay into a UK (or CI) bank account although this would appear to contradict some posts here. Possibly the best thing to do is to open a UK bank account BEFORE you leave UK - it is very much harder to do so from overseas, with the tightening of banking regulations (post 911?) but ensure you have VISA or some other Debit Card access, then as someone else pointed out it is a simple matter to transfer money at your convenience.
As far as the OAP goes, it will not be index linked after you start taking it at 65. This has been the suject of many court challenges and emotive rhetoric but IMHO will never change - the UK cannot afford to foot the bill. There was a recent High Court challenge from someone in SA, I believe, which got nowhere. Of course you can delay taking it, this might be beneficial if you didn't really need it and were in the middle of ultra high inflation, for example. Otherwise I think it is just a fact of life.
Having said that, I would highly recommend the move if you pick the right part of the country (no comment on this
Although the tax imposition is high, the cost of living is, conservatively, 30% less and your pension(s) will go a long way.
As way of a disclaimer, I do not claim to be a qualified financial adviser - these points are as a result of personal experience.
Bon Voyage!