I don't think my design is very good, if I spell it out what I'm trying to do you might have a better way of achieving what I'm struggling with, I'm pulling data from several different Excel worksheets using NPOI and then serialising them to a csv file using the class you pointed out a week or so back, all this is working well but I want to tidy it up. At present there are only three different types of imports but I'm sure this will change in the future - so basically I need to build a List for the serialiser of one of three
types