It will take time for me to get used to the different flush of our new toilets. I told R I wanted to take the cistern lid off but it wouldn't come off very easily. He told me, it is a brand new toilet. Stop being a control freak. You don't have to know how it works.
When we were installing the toilet roll holder, R remarked the new toilet was a bit strange in that the half flush was on the right and the full flush on the left. No no, I said, you are wrong. The half flush is on the left, as normal. It is not. It is so. It is not. It is so. We can be very mature at times.
I looked at my new toilet and R's new toilet and the half flush buttons were on opposite sides. I was hit with a moment of clarity. My issues with my new toilet were explained. I then timed them. My half flush went for four seconds, my full flush for two seconds. My half flush button was giving full flush and the half flush, a full flush.
It is quite true that the half flush should be on the left and the full flush on the right, but that is not so with these toilets. It won't worry me about the wrong flush for the buttons, I said to R, but then it niggled at me. However, given I just couldn't lift the cistern cover off, (where do you put the blue water colouring thing?) I need to search online.
Youtube to the rescue. https://youtu.be/6UhFv072tVM
Because each button had a different width tube to depress the mechanism, it was not as simple as just swapping buttons. I had to undo the plastic screw after removing the buttons and turn the holder 180% and then insert the buttons on their stems. Suddenly my toilet flushing problems were gone and our toilets matched.
It is still unusual that the half flush is on the right, and the plumber should not have made the mistake that he made by placing mine on the left, but I expect his instinct for half flushing button to be on the left came to the fore, and to fix it myself as against getting the plumber back to do so was a no brainer.
Blessed are those who upload Youtube videos about how to do things.