For a small 5-door automatic capable of towing a light trailer with dedicated wiring, your best options come from the Volkswagen Group and Toyota. These manufacturers are good for dedicated wiring because they offer towbar pre-installation from the factory. So the car already has the necessary cooling upgrades and a specific plug in the boot.

We'd suggest the Volkswagen Polo (1.0 TSI DSG) with a towing capacity of 1000kg to 1100kg (braked). When the trailer is plugged in, the car automatically adjusts the stability control, disables rear parking sensors plus alters the engine cooling map. The 1.0 TSI engine has surprisingly good torque for pulling a light trailer up hills. You could also look at the similar Skoda Fabia (1.0 or 1.5 TSI DSG). It uses the same chassis and engines as the Polo but is often slightly more practical with a larger boot and has the same towing capacity of 1000kg to 1200kg.

We'd also suggest looking at Toyota Yaris Cross Hybrid if you want a slightly higher driving position without going to a full-sized SUV. It has a slightly lower towing capacity at 750kg (braked or unbraked) but Toyota offers a dedicated 7-pin or 13-pin vehicle specific kit that integrates with the hybrid system. As a self charging it is incredibly efficient around town. The e-CVT automatic is very reliable, though it can drone slightly under heavy acceleration while towing.