>I have two related tables which have a one to one relationship, say for example 'customer' and 'bank account'

Are you sure one-to-one is appropriate here? (Hypothetically) What about multiple signature or multiple user accounts, or customers with several accounts? If it truly is one-to-one, the account data might be better served as just as extra fields in the customer table.

>I have a form which is used to view / navigate / amend customer details. The bank account biz object doesn't really play a part in this form with the following exception.
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>Whenever I create a new customer I have to create a new bank account record via the bank account biz object.
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>I've tried using the event class but I unsure if this is correct way to do it.

I haven't used event classes yet, but this seems sound.

Chris.