OK.....
Firstly I am not a new leaver.
I did however go from military rotary to civil fixed wing.
My general advice is do not take your 12 year option. Stay in the military if you can to accrue a pension,maintain a salary and keep some self respect. There are very few fixed wing jobs for ex military people as teenage wannabes are prepared to pay up to £100,000 for contract jobs.
If you have had enough of the military and really have to leave retrain in something else and take up gliding.