1) Of unclear meaning but probably some kind of timber framework for a well, perhaps in the shaft of a draw well.
Not uncommon as a minor place-name but not a recognised word in the vocabulary. It occurs several times in Yorkshire, for example: a.1189 Stockewell furlangs, Denby
1334 Stokwelleynge, Ardsley
1401 Stockwell Lane, Hedon
1637 the Stockwell Greene, Sheffield
1751 John Robinson ... was sinking a well at Hunsingore and had occasion for some old wood to make well stocks.