The whole of Geoffrey Klempner’s excellent course on business ethics – with many ideas which could be adapted for A level, is to be found on this menu (a set of pdf files).

http://www.isfp.co.uk/businesspathways/dilemmas.html#download

The Journal of Business Ethics has many useful articles for further research.  Here is the menu of past issues:

http://www.isfp.co.uk/businesspathways/index.html