Picture posting is enabled for all :)
I have not put mine to chit yet - better get on with it. But the bed is dug over and the bottle cloches all ready. I also put a plastic milk bottle full of water between each plant.
I think that you put a bottle cloche over the potato to keep the soil warm. The bottle of water between the plants is to do the same thing. The water in the bottle is supposed to warm during the day and let out its heat during the night. Left bottles of water in greenhouse over winter but with very limited success. However it was a particularly hard winter.