Any set-building advice? I'm hoping to add retractable wheels to a wooden phone-box...?

We've built a full-size, wooden replica of a red phone-box Three sides only, one of which includes the door), and want to make it easily movable. As people will be going in and out, we want it to be stable when it is stationary. How could we add wheels, and still maintain stability? Is there any device commercially available in the UK (eg for moving furniture) that we could use?Any set-building advice? I'm hoping to add retractable wheels to a wooden phone-box...?
You can get rollers with brakes on the little wheels. They are used for moving washing machines etc in and out of the fitmets. I think B%26amp;Q may do them but not sure.Any set-building advice? I'm hoping to add retractable wheels to a wooden phone-box...?
You could try taking the wheels off the phone box itself and fastening it to a platform with wheels on it. Then if you lay small tracks so that the wheels don't start going every which-a-way, you could push the platform onto the stage when needed and retract it when the scene is over. We did this in a very successful production of La Cage aux Folles. Depending on the production, you could also put the phone box on a turntable. Again, this would have wheels on it but bolted through the floor at the center and the phone box would be fastened to the platform of the turntable. Again, successfully done in Little Shop of Horrors