This is a small container found just off the footpath in Donkey Lane Plantation in Warley. But that doesn't really matter because I reckon you'll see pigs fly before you find this one.
Here's some local info:
"Donkey Lane Plantation was planted in the first half of the 19th century with sweet chestnut trees. These have been subsequently "coppiced" – cut to the ground – on a regular cycle to provide sustainable timber since the 1980s.
There is also a pond which is home to 2 newt species, smooth (Lissotrition vulgaris), and more importantly Palmate (Lissotriton helveticus) which has one of the largest breeding populations in the country."