Hi Merlin,
I posted a similar question here a while ago and was being quoted similar prices.
By far the best I found was b & q -- 6 * 4 for €148 and 7 * 5 for €164.
They are overlap sheds and some sales people say you'd be better off going for "shiplap" but at that size do you need a palace in the garden, for me its only storage. I am still looking but am hoping to pick up a b & q one at the weekend. Let me know if you find any deals