I can't yet find any reference to the heraldry I think you mean, and even John Howe (the artist that I think you are referencing here with this illustration) noted, about: "The Siege of Angband, Originally done for The Shaping of Middle-Earth"...
"This is perhaps the least favorite of my Tolkien pictures (barring a few absolutely awful ones which certainly won't make it on the site...) Angband is all wrong, the causeway and towers are ridiculous, the Elvish warriors in the foreground have awful costume and silly heraldry on dopey banners and the background is boring, though no worse than the swath of unkempt lawn in the front... well, okay, the flames are sort of all right.
Even worse, it feels like high fantasy, but certainly not connected to Middle-Earth. I wonder what I thought I was doing... but I'd happily do it again tomorrow if given the opportunity." So given that, I'm going to stop looking
http://john-howe.com/portfolio/gallery/ ... age_id=333