There's a good history of re-use throughout the centuries then.

This one:
http://www.themodernantiquarian.com/site/6185
was face down in the floor of a castle. Nowt ritualised about that. Face down in a church, that might lend itself to tenuous lines of reasoning involving ritual mentality.

Sigh. That's the problem* with this stuff.
Always more questions.
Rarely any answers.

*And half the fun of course ;)