You were right, it turns out that OFFSET prefers a blank as the width argument to a zero. This gave me the two columnar ranges that I was looking for.

The closest that 'Help' gets to being helpful here is that : "Width must be a positive number." I'm not sure if a purist would say that that technically includes or excludes zeros but now we know.

Thanks for your help, and Mark I appreciate your efforts too - I'm keen to follow up that union reference operator now - in conjuction with using labels in formulas I'm sure this could replace lookups with index/ match in some circumstances?

[ This Message was edited by: RaoulF on 2002-03-21 04:14 ]