In many cases a garden office can be built without the need to apply for Planning Permission. You do however need to follow the rules laid out by Permitted Development.
These rules state the distance different shape buildings should be positioned from the boundary. They also set the maximum heights of pitched roof garden offices.
With this video we have been able to show these different rules in relation to different shape garden offices in a 3D context.
httpss://youtu.be/6chmdVkkuuc
This video is designed as a useful visual guide. It is not intended as a definitive source you will find that on the Planning Portal.
The type of work you plan to undertake in your garden office may mean that full Planning Permission is required. Talk to your garden office supplier or your local Planning Department for clarification on your personal circumstances.