Are you seeing the expansion ring which forms at the point where the solid casehead makes the transition to the case wall? Are primers protruding? With a little right angled probe, can you feel a groove inside the casse about 1/4" from the base? Try sectionning a few cases. If there is a ring forming which will lead to incipient separation, you will see it.
What you are observing could be normal expansion in the often generous Lee Enfield chamber. This isn't the same as excessive headspace.
Is there a gunsmith in your area who has gauges? Supply houses like Brownells sell gauges.