Hornby Pendolino R427B

[BOLTSTE]

Hello,
This is my first post on the forum. I found the this site while asking questions generally to problems I had by using Google, and the respsonses to other questions from members looked like it was the place for me. When I retired five years ago with a disability I found I was able to indulge in what had always been an interest.
Which leads me to ask for help in replacing an X9708 coupling on a Hornby R427B. The task looks very different to the usual couplings , so I thought I would seek advice before I commenced. I have the X9708 and new springs which I think are the correct parts
Beginning with the body removal!

Any information would be much appreciated.
Boltste