Rowy i'm gonna wait until about 6 or 7pm tonight and see how much the temp rises as one of the other posts i read about the Belle Saison said to try and keep it around 19 or 20 for the first day and then let it rise on it's own accord but given the ****** unpredictable weather of late, i'm gonna use the STC1000 and hook it up to a heater pad to give it a boost. It's been getting colder and colder at night lately so i think the heater pad is the only reliable option for me.
You could try an electric blanket on the thermostat aswell, or depending on where things are in your house you could put it next to something warm. My keg freezer is in the laundry in a corner against the wall and whenever the freezer kicks in (about once an hour) it gives off a fair bit of warmth on 360 degrees. Since the laundry is pretty small, i could close the window and door and put the fermenter next to it (or anywhere in the laundry i suppose) and it would have a pretty stable temperature, my guess would be probably a reasonable 26 or so that you're after.
Not sure if that's any help or not mate but might give you some ideas,
good luck with it :beer: