The Piezo in my Flamingo is the series of clicks, not the single click like on some BBQ's. Yes, it will require either 240v power, or a battery.
Most hardware in the Jayco's are 12v, with the exception of the microwave and the fridge, when 240v is selected. So if you have it plugged into 240v and something is not working, either the Cetec is unplugged, or the item is broken. Check in the space behind the Cetec unit, it should be plugged into a power point. Also, for what its worth, I relocated my battery to this spot..
I can check the pins of the Cetec charging on the weekend for you, if it stops raining...
As for Charging on the road, I ran some 6B&S cable from an Anderson plug on the drawbar, into the battery compartment, via a 30amp circuit breaker, this is sufficient to charge on the road. I will be looking at running another set of cables to run the fridge form the car, whilst on the road too.
One last point, if you have the van plugged into 240v, the Cetec is on and working, and you plug the Anderson into the car, it will charge the battery in the car, albeit slowly as the Cetec is a trickle charger, but it works. I have dual batteries in the car, so it can charge the Aux battery while camping on 240v.