Basically the part about her missing half a payment is total rubbish, the bank wouldn't start repossession proceedings for something so trivial, it took 7 months of full non-payment before it got to that stage when my landlords property was repossessed.
With regards to repayment schedules, what you say is correct, at the initial repossession order what would have happened is that the court will have granted the bank a repossession order, which they then don't enforce if the person pays the agreed sum on time. If at any time the person fails to pay the bank can then go straight to court without involving the person and instruct a court balif to take possession of the property.
However.... at all stages during this process the person owing the money will be informed of the steps taken, and be able to be represented in all the court hearings.