My attitude is even simpler. The words are clear and ambiguous .“PLEASE CLOSE THE GATE”.
How much simpler can that be? But the prat in the van…?
Some folks don’t have thinking on the day to day agenda, that is so frustrating for a free thinker.
It is less than 90cm tall, lock the gate and make people step over - maybe remove the spikes off the gate part then it would be less than 80cm tall. Easy solve
The gate is 90 cm tall including the spikes. And the mail lady comes to the door so I don’t think she would like to have to clamber over the gate if it to be locked.
Put a mailbox on the gate, everyone’s a winner!
spoken like a true white van man
Yes - except the delivery was a package was too large to fit in the mailbox to it had to delivered to our door. It was a birthday from one of our grandkids.
There are exceptions to every rule, just deal with the day to day stuff.
I calculated 86 cm from the brick courses but 90 is fine, 80 without the spikes.
As some one said, put the mailbox at the property line like civilised countries do. 
There you go, all your problems solved! The power of a forum.
The ignorant driver ignored the clear notice.
The delivery would not have fitted in the mail box. Next …?
I am aware of such folks, not behaving like that, it is difficult to suggest a solution, the language problem could be a cause?
Easy - Just put it behind the wall… and ring you…
That’s what couriers do.
He just left it on our door. No certainty whether we were home or not. And he left the door wide open.
Perfect. If the gate was locked he would just leave it behind the wall, same result and no open gate.
Then somebody might nick it…