Yep bumper off matey
Pop the bonnet and look at the bumper just in front of the headlights they have a semicircular cutout on either side.
Look down through these windows and you will see the head of an allen bolt 10mm required if i remember correct down each of the windows.
remove all of the screws around the wheel arches and the lower edge of the bumper if any are still there then you undo both of the allen bolts i would guess you will only need to do the one not in the photo as i think your broken one may just twist off.
When these have been removed you can shimmy the bumper off parallel with the floor you will need to disconnect the electrical connector by the washer bottle to then fully remove the bumper .
It is a fairly easy job to do on your own although a little assistance is required to put it back depending on your patience level.
You are correct with your description of the replacement part required always good to buy the brackets that have had the height adjustment piece loosened you will see what i mean after you have removed it.
I can give you the number of a guy who can sell you the correct part PM me and i will send it you .