Q.Droopy, wilting leaves
I have a newly planted (autumn 2014) Conference pear with sad wilting leaves. I don’t believe it’s overwatered, as it’s in a well draining planter (120 x 120 cm) against a south facing wall. It shares the planter with some vigorous foxgloves. How can I tell if it is wilting from drought or wilting from over watering?

You need to feel the soil. Is it wet? Soggy? or Dry to the touch a few inches down?
You don't want the soil soggy, well watered and good draining potting soil.
From my research you will need to make sure you have the correct cultivator to grow a Conference Pear in a container.
Please read the links below with more information with watering and growing care needed.
https://www.gardeningknowhow.com/houseplants/hpgen/how-to-water-a-plant.htm
https://www.rhs.org.uk/advice/grow-your-own/fruit/pears
https://www.gardeningknowhow.com/ornamental/trees/tgen/bareroot-planting.htm