I'm stitching Celtic Knot Sampler at the moment, and using iron on bias. No problems stitching it at all. Just remember if you are using it, to use a hot iron and NO steam.
The centre block is 45" square, so instead of ironing it all on at once, I intend starting from the centre and ironing and stitching sections as I go. So far I have 9½ blocks of 12 done. It's my 'sanity saver' when I need something mindless to work on. :-)