Well, after picking at pritaeas's brain and with a little help internally, I have the following which did the job perfectly:
insert into dbo.tblBank_Indicator_List(Bank_ID, Demographic_ID, Indicator_Type)
select b.Bank_ID, d.Demo_ID, f.BEFI_ID
from dbo.tblBanks as b, dbo.tblBankDemographics as d, dbo.tblEconomicFinancialIndicators as f
This issue is resolved.