This is the Wrenn W4318P/A "Peak Freans" Ventilated Van in Dark Grey, running number DE 545533. Introduced by Wrenn in Period 2 (Triang/Wrenn) era they are becoming more difficult to find today in this condition. This example is from the Period 3 build and has pin wheel axles and metal rimmed wheels correct for the era.

Comes complete in Period 3 (type 7.5p) box and yellow plastic insert

Condition is "excellent to near mint" considering age.