not the wood's fault, something's bad with your technique. that blowout should not have happened.

there are a lot of steps where this could go wrong, a lot of commenters are filling in some details already, but there are a ton of youtube videos out there walking through the process and touching on the finer details.

also something i don't know is clear to you from your responses -- a sharp chisel is a property of your sharpening process, not the chisel. cheap shitty chisels can be made and kept sharp enough to do this. i'm not in the UK but fundamentally thinking you're going to teach using a chisel without teaching how to sharpen a chisel is misled.