I don't know when the floor was relaid.
I haven't asked locals about it yet.
My guess is that the stones were rediscovered when the floor was done and a friendly vicar decided to put the doors in as a way of attracting more people into the church.
Last time I looked the pulput had been screwed down over one of the stones.
I'll check the Wam index in the library and see if they throw up anything interesting.
PeteG