Ladbrokes did go NRNB last season for the major races at the start of the season. Not entirely sure what their plans are this year, but they are currently NRNB for the World Hurdle.
Oddschecker are particularly good for keeping track of this situation. If you look at the World Hurdle market, you will see a green and white letter "N" above their logo. Once you get closer to the festival they start to appear, and its quite useful I find.
Ladbrokes did go NRNB last season for the major races at the start of the season. Not entirely sure what their plans are this year, but they are currently NRNB for the World Hurdle.Oddschecker are particularly good for keeping track of this situation