I would start with:
A regulated entity must ensure that in all its dealings with customers and within the
context of its authorisation it:
2.1 acts honestly, fairly and professionally in the best interests of its customers and
the integrity of the market;
2.2 acts with due skill, care and diligence in the best interests of its customers;
2.3 does not recklessly, negligently or deliberately mislead a customer as to the
real or perceived advantages or disadvantages of any product or service;
2.4 has and employs effectively the resources, policies and procedures, systems
and control checks, including compliance checks, and staff training that are
necessary for compliance with this Code;
2.5 seeks from its customers information relevant to the product or service
requested;
It is not a huge leap to suggest that Banks may be under a duty to inform customers that they themselves have better rates and that are easy ways to switch or transfer funds.
Best interests of customers cannot mean low deposit rates and high mortgage rates.
Duty of care was not specifically stated but 2.1 and 2.2 are very strong. All CBI have to do is ask 'show me how you comply with 2.1 and 2.2 with regard to savings rates..'.