It's hard not to like Volvo's new EX30 compact crossover, its smallest SUV. Flawed genius: Volvo's EX30 lacks a dashboard behind the steering wheel Tweaking the side mirrors is also via the screen. looking at cars under £50,000, based on three years' ownership and 36,000 miles, says the seven-seater Volkswagen Multivan is the best performer with the slowest depreciation, retaining …