I presume by "code" you mean the seat class/bucket availability data...
This says the number of seats available for sale in each fare bucket. Although the flight has three classes, i.e. CW/WT+/WT, each of these classes have several different fare buckets that BA sells, e.g. CW has J (full fare, fully flexible), C (almost as flexible), D, R, I etc.. with I the least flexible. The data, e.g. suggest that there ae 8 CW seats left for sale.
Hope that helps,
tb