Richard, I am not responsible for the infographic, but to your question about coffee - it is the processing that is water intensive. Any processing for consumption purposes is a huge burden on the water table and is factored into the 'production' figures provided above.
It is almost lying to include rain fall use in your total water useage but exclude it from your "irrigation" sources. If rainfall is in your total it should also be mentioned in the water used in the UK since agriculture in the UK is rainfall based.
And why the heck is the water use of coffee so outragously more than rice? Coffee is not irrigated.