I've tried using the following and it has doesn't return what's required.
Q_Residual_ShelfLife_Positive: DMax("[W/E]","T_ODP_CumulativeForecast","[W/E]<=#" & [Q_Residual_ShelfLife_Positive].[W/E Despatch Date] & "#")
It seems to return a random date.
With regards to a unique entry, I...