Bumping this older thread.
I just found a similar stamp to the OP 1d KGV red. (Watermarked multiple crown and CA, so Scott 72). I can't match up any village or town, so am looking for help. This is a mint stamp, and the overprint is clearly impressed into the surface, showing pressure lines on the back. So, an overprint and not a cancellation, I believe.
Appears to be AVIUNI, but the right side shows a partial T (?). Thanks in advance.