I don't have the details for Wiveiscombe, but I do for London.
Both Fullers and Barclay Perkins had their own wells which they used as the source of their brewing water. Such waters were relatively low in sulphate but with reasonable levels of carbonate. The standard water supply, to which brewers would switch in the 20th century when their wells became contaminated, contained significantly fewer minerals.
Burton waters, on the other hand, often contained insane levels of sulphate. Though the exact makeup varied considerably, depending on the well’s depth.
|British brewing waters mg/l|
|Deep Well Waters|
|highest||lowest||Old London well water||London Metropolitan Water Board supply.|
|Total solids (dried)||2280.6||1225.8||461.8||319.3|
|Suitable for||Pale Ales.||Sweet, full stout not much used now).||Mild ales and stouts; with added gypsum for pale ales.|
|"Brewing Theory and Practice" by E.J. Jeffery, 1956, page 101.|