This is the Wrenn "Carter Aggregates" Ore Wagon in black with Load. Running number is No 7. Introduced by Basildon in Period 3 this was discontinued by 1980 - start of Period 4. Although one of the most common ore wagons that Wrenn, Basildon produced, it is RARE to see the Long Box version as shown in the picture. The wagon comes complete with Period 3 (7.5p type) Long Box, yellow plastic insert and cardboard packing pieces (2) stapled to the insert, correct for the period.  As with all Period 3 Wagons it has metal rimmed wheels.

Condition of the wagon/box is "excellent to near mint" for their age.