In many ways this is really good news from a research perspective. The guilds usually kept meticulous records of their tenants and sometimes their families, their leaseholds, the rents, the productivity of the land, etc. The extensive records of several of the London Companies are held at PRONI in Belfast, and give invaluable info on the people who lived on these lands. My own family rented Mercer Company land, and I found them in the rental records for several decades, answering many questions about their living conditions, dates of occupation and migration, who took over the property, etc. Good luck, Tim Kane Seattle