Do you share any sewer connection with your neighbours? If so, it's the water co's responsibility to sort out at their cost. If not, it's your responsibility.
Surprisingly low, if each peak is a whole day's usage. I'd suspect an issue with the Tado readings.
Gas usage for December in my 3-bed house averaged ~50kWh per day.
The angle isn't critical, but should be something like the original. You could likely improvise a guide/jig if you're not confident at judging the angle.