In Manage | Database | Fields, you can find and double click each of these fields to bring up field options. In this dialog, you can click the validation tab and then select "Not Empty". You can also specify a custom validation message that will appear when the user leaves the field empty and can choose whether or not the user can override the validation error.
Simply viewing the record does not trigger these validations unless the user actually edits the record values so this would appear to do what you need here.
Perfect - thanks. Thought it was something right in front of my nose!