Perhaps I could just spend a couple of minutes talking about how we do our reviews.
Quite often we will receive representations from particular businesses or from industry associations. When we receive these, we of course take a look at what the current rules are and how they will apply.
We quite often meet with the people who bring these requests to us in order to understand things better and learn as much as we can about the technology and the assets they're talking about. We can then supplement our analysis by looking at other factors, such as the accounting treatment of these assets.
We also look at studies on economic depreciation rates—studies that take a more academic approach—and we will often follow up with these groups and get whatever technical knowledge we can find. Sometimes this means we also have to consult with other government departments that have more expertise.