The South West Coast Path...

I am in the process of making a pebble art picture of Alfred, Mr K, and me walking the Coast Path in Cornwall. Here is the draft final arrangement of the pebbles. Now I just have to find a piece of 5 mm max thin board (so it will fit in the box frame), 23 cm x 23 cm, to glue them onto. Or maybe a canvas... wish me luck finding the right thing! :-)