With a GT (grand tourer), everything boils down to driving experience. That experience, however, is quite subjective. Do you want a sportier ride that can tackle track and run-of-the-mill asphalt? Do you prefer a luxurious cockpit that features every conceivable bell and whistle? Or is a mixture of both more your cup of tea?
In any case, your short list of possibilities should probably include the Bentley Continental GT and Aston Martin DB11. These exotic cars are the best of Britain, offering more extravagant features and power than your typical luxury vehicle.