Cobnut On A Walnut Tree?

Today’s picture is of a Cobnut on what we thought was a Walnut tree; clearly not. This is the first time any nuts have appeared, although in the Spring I thought it did not look like a Walnut tree. A while ago we planted some nut trees and obviously it was the Walnut that died and not the Cobnut as we had thought; maybe we should invest in another Walnut tree when the time is right to plant it.
 
Two new replacement doors have been fitted today, to match the ones already installed in the conservatory.  More confusion for Dougal and Florence as one of them now opens in the opposite direction.
 
It has rained on and off for much of the day although the sun shone long enough for me to take today’s picture of one of the three Cob nuts on the tree. As you can see the wire protection cage is still in place to protect the tree from the deer, but will the squirrels beat me to the nuts?