LED strip transformer installation

Hi everyone, 

I am new to this and a DIY'er so any help info would be greatly appreciated. 

I am installing new coving that is going to have RGB LED strip lights behind for mood lighting. As I need 2 x 10m runs I have purchased a 200w transformer which I will run the two strips off. 

The transformer is obviously quite large so it can't be hidden behind the coving. Therefore I was thinking of cutting out a square of plasterboard in the wall behind the coving to house the transformer. Is this safe to do? Is it legal? How would you hide the transformer for this type of job?

Many thanks for any help or advice! 

Cutting holes in walls depends on the structure and build type of the house.

How do you plan to power & "switch" these lights?

Burying it in the wall is unusual, how would you get at it for maintenance? Usually it would go in the floor/ceiling void.