I'm going back tomorrow to get compensation sorted.
I think "the best offer" you'll get is a free lifetime coffee/tea or £100 (whichever is lower).
But the limpwrists at the ICO have already said that they're going to go softly softly on enforcement this year, preferring education and improvement.
The Australian Competition and Consumer Commission is mandated to be champion for consumer law. The recent Australian Royal Commission on the banks have lifted a lid about how the ACCC works. One of the things mentioned is that the ACCC is (mostly) staffed by bank employees in secondment to the ACCC. These people help the Australian banks getting away with some of the dodgiest banking practice we've ever seen. This is also one of the biggest reasons why the ACCC is reluctant to go after the big four banks in Australia and instead, it goes after the small banks & business (like a bully).
Since Australian systems are basically a copy of the British system, maybe they have the same sort of practice (hence the "softly, softly" approach)?