Cherries are definitely in the harder to look after category. They suffer from many different diseases and pests.
Also need specific pruning to maintain growth and to promote flowers.
I think cherry should be OK outside through winter in most parts of UK but even on those small islands there's quite a difference in climate depending whether you are coastal, mountain, South or North.
Adding a general location (but a bit more specific than just UK) to your personal profile will definitely help others give you better advice.