Secret door

Mono Monday and today's theme is "Secrets".
Nothing inspired me on this gloomy Bank Holiday Monday.
We haven't been out.
I made some blackberry jelly, and then did a little research on Ancestry, as it is a free weekend.
Found no secrets there!

I was just about to go out into the garden for inspiration, when it suddenly came to me!
This is the inner side of our front door. Covered in random pieces of iron. (A new one has been fastened to the outer side.) 
Our cottage dates back to the late 1700's.and I'm sure this door must hold many secrets!
The tale we were told is that it has something to do with keeping the Luddites out!
I wonder!!!!