Over the next few months, there are likely to be challenges. As well as the ongoing 170 training 230 and MKIV training is going to be a factor, and as the weather gets warmer more people will be using up their annual leave entitlements as well. However, the training centres are still working flat out so hopefully now we're seeing staff numbers continue to rise we'll be able to see this current good patch of staff availability continue.
The W&B franchise has a very particular issue that causes it to need more drivers than normal. They have a lot of depots where trans are stabled and cleaned, but maintenance is only carried out at a few, with each of these depots maintaining different stock. This causes a requirement for stock to be moved to the maintenance depots at the end of the day during the week (and then back again the next day). In a bid, when looking to do quick unit diagrams, you might normally assume that the unit goes back to the depot it started from. At W&B that would be a mistake and would cause you to understate ECS mileage, and the driver requirement for such mileage.