Downpipe not in shoe

[JimFoster]

The downpipe is about 2" too short to fit into the shoe. The shoe was badly fitted and cemented in any case. I'm thinking do I cut another section of downpipe which will fit snuggly. Or can I just use a socket.
http://www.screwfix.com/p/down-pipe-socket-black-68mm/17914

 

[Mw Roofline]

If you use a socket, you'll still need a tiny bit of pipe for the bottom of the socket to go into the shoe or the shoe will drop off. Unless you wedge it with something.