If the person who died used a bank to draw up their will and appointed them as a co-executor, they might suggest they act as a professional executor and carry out probate.
In fact, in the past some have tried to insist on this.
With this arrangement, the bank tends to charge a percentage of the value of the estate for their services.
In some estates, this could mean tens of thousands of pounds in service fees.
You could ask the bank to step down as executor, with the agreement of all beneficiaries.
But if the bank refuses to renounce its role, you might have to apply to the court to remove them.