Has anyone built a garden room/studio/office?

[BikeChick]

We are considering a small garden room to use as a small gym area for indoor cycling during the freezing months and when we are home alone parenting (one of us travels a lot). It would not need to be huge - basically a very good quality summer house with doors/windows/good locks/lighting and power. Has anyone added anything like this to their garden? I am wondering if I need to go with a special garden room company or if a builder/garden designer and landscaper could do it? Any recommendations would be most welcome. The garden room companies seem very expensive - like around ?10k.

Thank you!

[Garveyplumbing]

I'm in the middle of building one now and I'm spending around ?7000

Pm me for more details

Regards

Lee