Unfortunately it looks like I have stuffed the sleeve - how do you normally get a sleeve out??

Couple of ways of doing this.. First of all - Does it move at all ?

When they don't move, you need to break the sleeve. What I do, is use a tool which is a long thin screwdriver - Just push the screwdriver inbetween the coil and the sleeve and "break" the sleeve. Move the tool or screwdriver along the sleeve until it has completely collapsed.... Remove the sleeve..

When installing the new sleeve, if you feel resistance, just spray a little bit of Nifti on the foil sleeve and try again. If you cannot push the sleeve into the coil, then the coil is no good.