This is the Wrenn W5006 Ore Wagon "Southdown" in grey with the YELLOW running board transfer not the more common green., Running number is "17 York". and was introduced by Basildon in late Period 3 into Period 4. This Period 3 version has "metal rimmed"  wheels, standard issue for the P3/4 eras..

The Wagon is currently available with Period 3 box, and yellow plastic insert..

Wagon/Box is "near mint" considering their age.