I'm not sure whether the thermostat is detachable from its housing, but the part number for the 1.5dCi thermostat and housing is 1106000Q0N. It's shared with the Renault Megane, amongst others.
The valve opening temperature for the 1.5's thermostat is stated as 83°C / 181°F in the workshop manual.
Some J10 1.5 thermostat/housing replacements are rated at 89°C / 192°F, which would make the car run hotter and be better for very cold weather, but I have no idea whether they're compatible with a J11.
2015 1.6dCi 130 Xtronic N-tec+ in Gun Metallic Q-Day was Thursday 23-07-15