Possible Clues:

• Construction workers
• Constructors
• ... their old money, trading capital for a billion workers
• They're doing the spadework for The House and for the homemakers
• Working on a home away from home, they're responsible for first five characters in 5 down
• They do all the housework for those looking to set-up Home Farm perhaps
• They're great ones for a quote as they set up house
• Civil engineers