That's life these days Dave.
Replaced the door closer on our screen door a month or so ago.
Simple I thought. Just get identical unit and merely replace the cylinder thing re-using the brackets on the door and the door frame.
Oh dear me (or words to that effect)..................
Tongue on the cylinder is a bee's dick larger - drill out the pops and replace the door bracket with the one supplied.
Piston rod is larger diameter than the old one and does not fit the hole in the door frame bracket .
Replace the door bracket with the new one - no the screw holes are a different spacing.
Drill out the rod hole in the old bracket so as to reuse the existing frame holes.
Yippee it works. Only took two hours instead of five minutes.
How will the next generation cope? No drill, no pop riveter, no bloody idea. On the other hand they can, no doubt, drive a smart phone which I can't.
Geoff