I finally braved the cold and finished fitting the part. I am not proud of the installation of the split pin. I could only get one hand in to hold it, and bend the legs. I'll maybe take another look when it is warmer, meanwhile I secured the bottom end of the cylinder, and refastened the right side of the rudder assembly. As this is only the co-pilot side I guess it is not critical.
While on-site I spotted another small puddle of petrol - seems to be coming from the gascolator.
