K12 rear bumper removal/fitting

Hi all,
I have been searching the internet for instructions on this and am surprised not even YouTube has anything!!
So found this forum which is great.
I need your help since there's a lot of knowledge here on the forum.
My wife has reversed into a bollard and put a big hole in the rear bumper so I said " hang on I will replace it for you " problem is I can't find a guide on how to do this or even where the bolts are located.

Please please has anyone done this before who could shed some light on this.
(Also if anyone has a rear bumper for sale must be in dark grey to save me having it painted.)

Your help is much appreciated