For some selections in particular activity screens, it is necessary to make a selection in the field directly above the field in question, before the field in question will display information for you to choose from, i.e. you must fill out the fields in order from top to bottom. 

The reason for this is to ensure that the excel spread sheet is uploaded in accordance with the country specific standards and methodologies. For example for calorific value basis, the units must be chosen first.