How do you change scaling on a wind_rose legend?

Hello,

I am using the wind_rose function to plot a direction against intensity. I have been able to plot what I needed using the following code:

    % code
  end
D=xlsread('July 2013.csv','O14:O1091')/100;
I=xlsread('July 2013.csv','L14:L1091');
M=mod(I-180,360);
h = wind_rose(M,D,'dtype','meteo','n',12,'lablegend','Hm0 (metres)','ci', 0:10:60,'quad',[4]);

However, the legend that appears shows 12 colour boxes going 0-0.1, 0.1-0.2, 0.2-0.3 etc, I would like there to only be 6 colour boxes going from 0-0.5, 0.5-1 etc. Am I able to scale the legend somehow please?