I thought I'd let you know about our 2013 Holden Colorado, which caught fire in our backyard. We still don't know the cause as the insurance paid the claim without investigating and Holden wiped their hands of it. There were no suspicious circumstances; the car was turned off for nearly 3 hours before the fire! I believe the fire was caused by a fault with the car. We nearly lost our home and potentially our lives.
In 2015 Holden recalled 26,000 Colorado utes and SUVs because of the chance they might catch fire. The affected models were made between September 2013 and January 2015, which fits with your car. According to the Federal Government recall website, "there is a risk that cable insulation may melt or catch fire." For its part Holden said that an alternator cable might have been assembled so it makes contact with a steel bracket on the battery tray. The insulation could rub through, causing a short circuit, which could lead to a fire.