[MattW]

I have taken them on Easyjet recently. I put them in the checked in bagage.

I believe there is some ruling in the US (or it could be that I dreamed it!!!) that says for LiPo batteries you are allowed to take one battery in the item (i.e laptop/camera!) and one spare. However, when I searched for this before I travelled I coudln't find anything about it.