If said bank did commit such an act and a fine was the punishment then yes. They should be fined appropriately. They should be fined what was laundered & double it. Banks should never take advantage of having money at their fingertips. We all trust our funds will be safe within the bank.
Not only should Standard Chartered be fined they should be forced to close. Money laundering is illegal, no grey area on that. Laundering for Iran, even worse. This is a big bank and they know better. A fine in the billions is warranted and then a force close to follow.
The larger and more important an organization is, the higher standards it need to be held to. A major international bank absolutely must run a squeaky clean operation. A corrupt or "dirty" organization of that size could cause serious problems for the the economy of the entire world. Even if Standard Chartered is innocent of these particular charges, they are guilty of failing to run their organization in such a way to make it 'above suspicion'.
The British band should definitely be fined for money laundering because it is illegal. Anyone person or business that is involved in money laundering should be fined. Especially a bank with as much prestige as the British bank. An example needs to be set with them to deter others from doing the same thing.