How do I access the other mounts in DAI?

I've been perusing these help pages for the last few hours searching for someone who could answer how I get the bonus mount content ... i.e. the Flames of the Inquisition Armored Mount, the Red Hart and the Bog Unicorn. I finally got the mounts (sorta)

After talking to Horsemaster Dennet and then picking up the other quests at the farm I went back to Haven because I got a notice saying my Ambassador had finished her War Council quest to get me gold and being the greedy player that I can be I wanted that gold 😕mileytongue:

Upon my arrival in Haven I did check the chest again inside the house you first wake up in after the prologue quest, just to make sure the box didn't have anything else for me ...which it didn't ☹️  (yes I did get my armor and weapon from it already.)  So now I went to get my gold and upon entering the war council room I see much to my surprise and delight 3 NEW  quests on the map ...one for each mount I am due for buying the deluxe edition :D

My question is: how do I access these mounts? when I went back to the Hinterlands and summoned my mount the only one available is the generic mount given to me by Horsemaster Dennet. I got no pop up menu asking me to chose a mount to use, just a whistle and then the regular plain jane mount showed up. The very first creature listing in my codex details all three special mounts yet I can find no way to access any of them so looking for a little help here thx