Using Conditional Formatting on Text value to show Icons - Icons Not showing

HI

I have Text columns that I need to use icons instead, based on warning status of each wording.

I have used a Conditional Column in queries to add a numeric value based on text, which works fine i.e "Critical "= 3, "Warning" = 2, "Ok"= 1 and n/a = 4, I then changed the format of the column to decimal number.

I then add the new column into my table. Numbers show up fine.  However, when I go to add the icons to these numbers, see attached image, and press ok, NO icons appear in my table, numbers still just show.  I have gone back over my steps above and everything seems to be in order, so bit lost as to why the icons are not showing.  Any help would be appreciated.

Thanks

Ann