Yes, Chrissie and Irene you were right it is a ribbon box! I've seen them on people's blogs and for sale already full of ribbon and always thought they looked good. However, I never really had enough spools of ribbon to bother before. I usually buy my ribbon in lengths and not on a reel, but after the great sale at http://www.artymiss.co.uk/index.html and 20 spools of Dovecraft ribbon falling into my shopping basket I found I had enough to fill my box!I used a Japanese screw punch to put the holes down the alternate sides of the box as it was big enough to have two rows of ribbon. I found after threading the first row of spools of ribbon that we had a major design fault. There was enough space for the ribbon to roll back and come unthreaded!
It might have been okay when both rows were in place but I decided to take no chances and put a card support in as shown in the photo below to hold the ribbons in place.

Just got to decide how to decorate the box now.