Changing Armrest-Help required

[mercfunder]

I am trying to change the armrest in my 2003 X type.
The current armrest clips in on a clip running front to back, whereas the new one has a clip which runs left to right.

Anyone know how to change over the piece in the centre console that the clip goes into?
I am assuming I can get the part from Jaguar and then hopefully change it over, just can't seem to see how it comes out.

Any assistance gratefully received.