Fiscal Agents and ethics

I am dealing with a £5 million t/of import partnership business. As you know partners are assessed individually like sole traders. The partnership is not assessable.  I see that a 'TR bank account exists as well as a bank current account. The bank credit the TR account with foreign bills payable  and at a later date the bank current account pays the TR account.

The entries when discharging the TR liability are 

Debit      TR account

Credit    bank current account

I see that 10 years ago the bank TR account was debited with

£12000

£15300

£10250

But the bank failed to credit the current account with the above 3 figures. This means that the bank have lost £37550 by poor accounting.   In the partnership accounts the  £37550 lies dormant as a creditor.  The partnership is indebted to the bank unbeknown to the bank.

If you know of a mistake which favours you surely if you do not advise the creditor your actions are deemed as theft.

The fiscal agent will have mentioned the mistake of the bank to the partners but whose responsibility is it to correct this mistake. What are the ethics.  Is being hush for 10 years okay.