Trade in or wait for a D4?

With a D4 HSE listed at £52,450 and an Evoque Dynamic at £39,925 its a no brainer, you've got to swap, the equivalent of a £13k discount on the Disco and zero depreciation on the Evoque. We've owned several Disco's over the years and they are great family cars, our Evoque is suitable the two of us but I don't believe it would be big enough for a family of four. A word of warning, beware the depreciation on the Disco, our experience was around 40/50% after 3 years.
Tim