I had planned to go with this stuff:Matt blackboard paint. I gave it a rough key with some course wire wool and then that was two coats with a gloss mini roller which got the finish
I used this paint from Amazon. It was the best value for the smallest tin as you don’t need much at all. But I’ve got plenty for other blackboard projects around the house.
http://rover.ebay.com/rover/1/710-5...0001&campid=5338413729&icep_item=391986107745
But looking at the cracking finish you've got, I think I'll get the same as you did!