Whiteheads Torpedo factory was opened in 1891, testing took place in Portland harbour. At the beginng of the second world war some 1500 mem and women were employed on the site. After the war the demand for torpedoes fell and the factory found itself in difficulties and so started making other products. The factory was purchased by Wellworthy, a company specialising in components for the motor industry. By 1993 many of the parts of the original buildings were no longer useable and so in 1997, after 106 years, the old factory was demolished to make way for a housing development. Before the houses could be built the site had to be enviromentally cleaned due to the amount of contaminates that had been used.
You are looking for a small round cache container (3cm diameter), the area is very busy so caution and discretion will be required.
Congratulations to Streaky/Sue FTF