Insect on window glass (Rhyssa persuasoria?)

I an not an entomologist, but this looks remarkably like a photo in a book on wildlife.  If correctly identified, this is Rhyssa persuasoria, an ichneumon fly (don't ask me!). 

"Female uses long ovipositor to parasitise larvae of giant wood wasp which are located deep in living timber"

This image can be confusing: what I am photographing is the top of the insect, which is shaded.  Its legs also look confusing, but don't work ... it can walk perfectly.