It sounds to me that the temperature sensor arrangement has quite a low source resistance, so you can connect it directly. Can you provide a link to the datasheet for the sensor?
If it's on a long lead then you might want to include a 10K resistor between the sensor and the analog input pin, and a 0.1uF capacitor between the input pin and ground.
Nah no datasheet for it - though it's just a NTC 25 deg C 10k sensor.
Long lead --- from the sensor to the controller - yes, from the controller to my controller? Not so much
Can't hurt to have 10k resistor and the cap - so I'll add that.
Will test it today, connect the arduino direct and measure sensor voltage before and after connection, with any luck it won't change much at all..