Dave C

Nothing to take out on the narrow end, as the end of the Rose joint is the seat at that end. 
did you smooth off any damaged metal on the arm end, as in my how to?

Has the narrow end aperture been deformed in any way?

I inserted the bush by using a vice, what are you using, if it's still attached to the car?
 

Yep, still on the car.  No damage at all on the narrow end, I got it out quite cleanly on both ends to be honest. 

I have been using the threaded bar with nuts and washers to try to get it in.  I can't get the fully assembled poly bush in as the poly part starts to crush up and the centre tube starts being pushed through on its own.  So, I get the bush in first and then try to wind in the tube with the threaded bar method and it gets through the arm but splits the bush as it is doing it.  I know they have to be tight but it really feels like a quart into a pint pot.

I have measure the OD of the metal tube, it is 2cm.  Does that sound about right as looking at the pics the thickness of the wall of the tube looks thicker?