How do I lookup from column A and B so that the resultant answers are
put in columns D and E? I can do a single element Vlookup but not sure
about two columns of lookup.

I have Surname, Forename, Age, House name in my table.

If I key in a surname, I want the system to check for a single
occurrence of the forename to prevent duplicate names. It then must
give me the age of the person and also their house name.

e.g. Smith, Jimmy,23,The Gables

Jonah