Quick Answer
For UK riders with up to £1,500 to spend, the sweet spot is a well-equipped 250W EAPC with a useful battery, dependable brakes and a frame designed around the rider's actual use. At this budget, the strongest choices include folding commuters, step-through city bikes and capable fat-tyre models. The right bike is not necessarily the one with the biggest claimed range or highest headline motor figure: weight, comfort, braking, battery quality and support matter just as much.
Among models currently listed by ST3IKE, notable options around this budget include the ENGWE L20 3.0 Boost, ENGWE E26, ADO Air 20 Pro, ADO Air 28 and ENGWE EP-2 3.0 Boost, subject to current price and availability.