That has worked for changing times for the heating.
But for the hot water, I have been pressing PROG, changing the time for the first time event, pressing NEXT to move to the next event and so on, then pressing PROG.
But when pressing PROG again to check the changes have been saved, the original times are displayed.
Also, pressing PROG for the hot water (tap icon) only moves me forward when I have pressed MODE and the wavy line appears.
Yes, I have already tried that.