I suppose the barrows show use of the area for burials over quite a long period of time:
‘The Knoll’ is described as a bell barrow at magic.gov so will be the burial mound of a wealthy Bronze Age person.
A bronze dagger was found in the excavation of a bell barrow at st91284150, according to magic.gov – but I don’t think I saw this barrow at all (only 3 are on the OS map, but their map shows 4).
ST91124151 is a longbarrow – that’s the middle photo – so that’s neolithic. The other photo is of a bowl barrow, so perhaps that was built in the late neolithic/early bronze age – in the time between the long barrow and the Knoll.
Also, between the bowl barrow and the others is an (almost) ruined church with its graveyard, unusually dedicated to St Leonard – interesting as another layer of ‘burial history’ in this relatively tiny area.
Heytesbury isn’t far away – you might want to pop to that church to visit the mortal remains of William Cunnington. A tablet inside the church has an inscription purportedly written by Richard Colt Hoare.