Confidence: It might be this.
Notes: From the limitations of my field guide this crane fly seems to be like a male spotted crane-fly but with a dark stigma and a dark streak in the wing. Found in very wet woodland alongside a pond which seems to be the right habitat HOWEVER the book says that this species rests with its wings folded flat over the body and this one obviously has its wings out stretched. Is this just an immature T oleraceae? Just not big enough as far as I can tell.