Decorating a children's playroom.

We are looking to decorate a children's playroom. The rough dimensions 3 meters by 2 meters. It's currently is a grey box, in the garden. We have put some toys in there, but the kids aren't interested in playing there. The kids are very young (one and half, and almost 3 years old). We are currently just wanting to do it up, so it wow's the kids. We have seen children's wallpaper that might be suitable and I have included a wall mural that is from Wilko's for one of the wall. The link to that is below. [login to view URL] The rest of the room is the harder part. And this is where you really come in. There is a plain wall to the left of the room. The wall to the right has a window in it. And the wall towards the garden, has a large window looking into the garden, and two wooden doors (this wall will probably be the most challenging). We are looking for one of two things. 1) A room completely decorated and painted by yourself. Something that will wow the kids for sometime to come. But this will take time, and therefore cost will be greater. 2) Or, a room with one or two mural wallpaper, integrated with your skills and talent on the wall with the window and the wall with the window and two wooden doors. We are open to ideas, both in terms of the walls and other suggestions. Also, at the moment, they don't have their own bedrooms, this will change in the near future. And so there is another project that we will need help with, in the near future. The house is located in South London (Norbury SW16). When contacting us, if you could give us two quotes and a rough timeframe of how long it will take. all the very best