This can be done as a cache & dash as there are a couple of places to pull in, or if you prefer part of a longer walk around the area as there are many footpaths, tracks & lanes to explore.
The barrow itself is under the island of trees you can see with the large one sticking out the top, folklore says there is a Saxon Chief killed in battle buried within and that an Oak or Elm tree that grew on the barrow until 1937 would bleed when cut with a knife. The mound was excavated in September 1815 by Revd Skinner with the help of local coal miners but when they got to the middle they discovered that someone had already beaten them to it and had robbed it of its contents. The cache is hidden within reach of Public Footpath so I can't say for certain if permission is needed to explore further.
You are looking for a small clip lock container that contains a logbook a few swaps and a small prize for FTF, it's big enough to take trackables and please re-hide well after signing the log to record your find.