Forster was assessed for the tax on landed incomes granted in his third Parliament as receiving £5 p.a. from his holdings in Wiltshire. Although their location is not always certain, he may have been the man who in 1436 acquired property in ‘Great Sheepbridge’, where a namesake had previously held land in the first decade of the century, while in the county town of Wilton he is known to have owned a messuage and four acres of meadowland, which eventually passed to his son John.
How often or for how long Forster occupied positions of authority in Wilton is rarely recorded, although in February 1436 he served as a juror for the inquisition post mortem on John, earl of Arundel,
