You'll probably find that you let the sealing washer slip off
the land next to the manifold, that's why I warned to watch
for this in the guide, and then deformed it when tightening.
You will need a new Jet and sealing washers from a scrappy
or from someone on here who deals in used/ new spares.
In the meantime, see if the water hoses will remove from the
banjo easily without breaking. If so, join them together with
a piece of tubing, either internally and use the existing clips,
or externally and use a larger pair of jubilee clips.
This will allow you to drive the car without losing coolant.
The old Jet should remove easily, if you've sheared the end
off it there will be no torque to overcome. Either use a screw
extractor as in this link
http://www.screwfix.com/prods/20084/Van-Car-Accessories/Mechanics-Tools/Stud-Extractor-Set-8-Pcor try wedging a tapered dumpy screwdriver in the remains
and see if it will turn it out. Don't do this if there is any chance
of damaging the inlet manifold thread (the bit that the Jet screws
into)
When you do it next time, ensure the sealing washers are
correctly positioned on the lands of the Jet.