Good afternoon!
I have discovered in this website of the Catholic University of America that it is possible to download several numbers of the 'Inter-University Magazine':
https://cuislandora.wrlc.org/islandora/object/cuislandora%3A79145
Unfortunately, the sample that probably contains the poems 'Tinfang Warble' and 'The Grey Bridge of Tavrobel' (vol. 8, see https://wayneandchristina.wordpress.com/2013/04/19/tolkien-notes-6/) only can be downloaded by the university members. Maybe, one of you have contact with any of its members.
Kind regards.