So I bought something that was too big and I didn't return on time. Had the amazing brainwave to wash it and run it through the tumble dryer (label said not to) and hope for the best.
This did the trick and it fits perfectly now. I'm quite chuffed with myself 
But my question is, now that I've shrunk it a bit can I tumble dry it every other time too? Is that it shrunk as far as it will go or could I shrink it further and best to just wash as per instructions from now on?
I don't want to get carried away with laundry bravado.