[Andmurph]

Could it be dirt in the thermostat in the floating console? I know you say it holds 21c but I’ve found on my V70 the thermostat slots seem to attract debris, especially dogs hairs. It’s a car not a kennel and certainly no dogs allowed but their hairs still get in on clothing. A clean with a vacuum may work. Accessing the thermostat is easy enough if you remove the floating console. The thermostat on mine has a fine bimetallic strip that I cleaned with acetone while I was in there with anti rattle tape.