I am pretty sure NTSC version was never released.
https://www.mobygames.com/game/13810/ivanhoe/releases/
There are not any reviews in USA based computer magazines:
https://amr.abime.net/amr_search.php...=0&action=Find
Also if they would have planned to distribute in USA, they might not have printed £ prices with big numbers in the boxes.
https://amiga.abime.net/games/view/ivanhoe#scans
Only one version here for Amiga:
http://www.softpres.org/games