@markderrick I did think I might have to pull out those that need setting to blank but as I was saying you can default the value to "Null" at the point you map the values so I wondered if supplying that value in the CSV would work. Looks like I'll have to give it a try! Thanks for the responses though and I learnt something new! 😉 (need to pay more attention to options, I'm a bit "auto-pilot" with some tasks!)