Other impacts are less obvious, as with the pipelines laid across the battlefield 1969 and 1984 (Figure 5.6). The construction corridors for the latter were approximately 20 m wide, judging from contemporary aerial photographs, but about half of the width was taken up by spoil so was largely undisturbed. In the other half topsoil was stripped and placed immediately adjacent and so, on reinstatement, the topsoil and the artefacts within it are likely to have been moved no more than a few metres from their original position. Given this, and the fact that none of the round shot came from the construction corridors, it is likely that the recovery location for most finds is very close to where they were deposited in 1485.

A far more selective mechanism which may have removed round shot on some battlefield is the use of machines to collect potatoes or to de-stone the ground, for which anecdotal evidence comes from Edgehill.⁴⁹ Although it is understood that potatoes were grown on part of the western area of Bosworth battlefield (Upton Hall farm) before the mid-1980s, farm workers have reported that the potatoes were hand picked not riddled by machine.⁵⁰

On many battlefields the greatest loss, and the most worrying because largely unquantifiable, has been that caused collectors using metal detectors during the last 30–40 years. The impact has received most publicity at Towton, but losses are also known on various other battlefields of the period, including Barnet and Shrewsbury.⁵¹ Fortunately, because the Bosworth site was lost, and thanks to the attitude of the main landowners towards treasure hunting, almost nothing from the core of the battlefield seems to have been lost to collectors. Even illicit detecting on any scale is improbable, given the presence of several farms and other houses in the heart of the battlefield. The only collecting that has taken place with landowner permission is on the periphery of the battlefield, in areas of different ownership further to the south-east and east.⁵² Even there the impact seems to have been minimal, in large part perhaps because of the very low density of finds of any date, which will have discouraged detectorists from returning. Thus there is every reason to believe that the pattern of round shot and other artefacts seen at Bosworth has not been significantly distorted by losses to collectors.