Allied Dunbar's business, like its predecessor Abbey Life's, was unit-linked: the direct investment risk and reward due to market changes was very largely exclusive to the individual investors, rather than the company, its shareholders or other planholders.
Its initial sales proposition was to offer unit-linked Bonds, which could be sold door-to-door (unlike unit trusts at the time), and including property investment (when property unit trusts were not then authorised.