This is from the Bristol & Avon Archaeology journal volume 8, 1989:
"As well as relict field boundaries, Stoke Park contains the remains of several "pillow-moulds", banks thrown up to encourage colonisation by rabbits, and probably dating from soon after the construction of Stoke House in the late 16th century. "
"Some 300m to the north-west, on the crest of the Purdown ridge, is another probable pillow-mould, running NW-SE and approximately 20m long, with a shallow ditch enclosing its squared northern end (ST 61327728; Fig. 2,F). This feature is one of a number of earthworks on Purdown which were claimed as prehistoric by members of the University of Bristol Speleological Society in the l 940's (Crook & Tratman 1948, 48-9) and is still shown on Ordnance Survey maps as a Neolithic "long barrow". Extensive excavation by the Folk House Archaeological Club in 1954- 5 (O'Neil & Grinsell 1960, 68) and by R. Iles & V. Russett in 1984/5 (Iles & White 1986, 53-55) has, however, dis- proved this interpretation and indicated a post-medieval date for the earthwork. The mound was in existence by 1725 and is shown as a tree-covered "Tump" on Samuel Cook's plan of 1749 (GRO D2700 QP 15/7)"
So just some old rabbit warrens that some over-excited people thought were ancient barrows back in the day.
Something is not right. This message is just to keep things from messing up down the road