My point is that it's not going to be simple for them if they decide to try and do so.
If they try to claim the money they may get ruled against by the courts.
My guess (and it is just a guess) is that they won't try to make it apply retrospectively. The sums involved are relatively small compared to the ongoing revenue stream so it's unlikely to be worth the legal hassle of the inevitable challenges.
My point is that it's not going to be simple for them if they decide to try and do so.
If they try to claim the money they may get ruled against by the courts.
My guess (and it is just a guess) is that they won't try to make it apply retrospectively. The sums involved are relatively small compared to the ongoing revenue stream so it's unlikely to be worth the legal hassle of the inevitable challenges.