If anyone is interested...
Well it didnt start this morning, started wearing the battery out so I phoned, Ford Assist and the technician from Ford assist just tapped the LPG piston that the user below is talking about and it started up no problems. I than took it to ford and they replaced it under warranty.
He said it was a pretty common issue, so thanks for the replies !
This is an excerpt of a post from a user on fordforums.com.au,
Thanks to Calaway and also in some respects Charger from CAA.

QUOTE
Two things that are a problem with these systems - The solenoid casings crack particularly the one at the fuel line lock off on the converter. Also in some cases the heater hoses leak coolant which drips into this cracked casing causing non starting.
However, based on what you descibe the problem will be the lock off or possibly idle solenoid piston sticking in its bore. LPG wax builds up on these lock off pistons. On first start (when the engine is cold) this wax causes the piston to stick and basically speaking, no gas flow. Normally by tapping the lock off or switching on and off a few times unsticks the piston. A simple fix, remove the piston and clean with a solvent. Must be done by a suitably qualified tech.
Make sure that you are very specific when speaking to whoever is servicing you're car as most people are not aware of this problem.