This feels like an extremely n00b question, but here goes...
I have a series of HTML files with a small amount of HTML content inside each (exported from a live system).
I worked around the problem by adding a config variable which is then used in a string replacement call to replace an export-generated string with one which someone can update in a config file, before burning to CD. I can get away with this because the string replacement is essentially the only PHP in these HTML files. I'll close this question after... leaving for anyone to check up on/read about quickly.