The binmen haven't emptied it. Instead they hung a note on that reads "OOPS! WE HAVE NOT BEEN ABLE TO EMPTY YOUR BIN TODAY. Your recycling bin has not been emptied because it contains items that we cannot recycle or compost.
Please ensure that you remove the items (listed overleaf)so that we can empty your bin on the next collection day"
So I turned the tag over and they have checked the box for garden waste. 
In what universe can garden waste not be composted? Might have to leave a scathing comment on the website. Or just whine on MN :o