There are plenty of EVs that offer a good towing capacity, but many of these are more recent models so there is a more limited choice within your budget. The MG ZS EV has a towing capacity of 500kg which may be sufficient for a small trailer, but probably your best option would be a Hyundai Ioniq Electric, as the 28kW version has a braked towing capacity of 750kg and should be available within your budget.