On this image you can possibly see the 'scoop' opening as appears in the original image. There was also a development of this missile with similar nozzles - AS.12. It doesn't fit with ident of AS.12 as this was quite larger. I'd still go for the AS.11 / SS.11. Image of '11':
Very good advice on the reporting of it. Let the experts remove it and identify it - post back with any ident you might get from EOD!