Exactly. They do not manufacture a 1.25" blade holder for a BXA toolpost, heck not even a 1.00" holder. All that Dorian offers is .75". On a 14" lathe that seems awfully inadequate, especially since there are other out there with much better specs.
Check with Matt at QMT, he sells Aloris. Ajax is another supplier, they are all within a few dollars of each other.
JTS machinery & supply sells a bunch of Chinese holders for for different blade heights, the holders mount in something like a #1 or #2 holder. I can only find this in their catalogue, the website is pretty bad. I have some oversized holders, so my parting blade is in a 1" Dorian BXA. You can run into some height adjustment issues.