Unable to print custom print size

I've seen other users with the same question but they have different siuations to me (and some are quite old) so apologies but can someone please tell me how to print a 12inch by 15inch PDF (That's landscape). I'm printing from Word to the PDF Creator printer. I go into Printer Properties/Advanced, select the Postscript Custom Page Size and set it to Width 15 inches, height 12 inches. OK that and print - and I get a landscape US Letter sized document. If I select A4, I get A4.
I saw on a previous post about creating a custom paper size using Windows Print Management, which I have done. I can then select this paper size but it still prints a landscape US letter sized document.
Interestingly if use the PDF Architect printer then it happily prints the 12x15 document - but then I can't select the PDF Creator profile that I have set up to specify PDF/X and CMYK (which are required).
Any help gratefully received. Windows 10 and PDF Creator 4.1.0