The problem was that it was difficult to flush the toilet; sometimes one had to press the button several times before it flushed. I fitted the kit, which was straightforward, but then it was even more difficult to flush! I tried experimenting with keeping some of the old components, without improving matters. Then I tried cutting about a foot off the tubing (using the old components) and this made a big improvement. I may try replacing the chrome plate which contains the buttons, which don't fit so tightly into the new bellows, and see if that works.