Both of those come up constantly. Search on the forum for 'Vehicle Excise Duty' and you'll find a few threads, I think. As for compulsory registration, none other than Ken Livingstone floated that one a few years ago, and we had a pretty good and effective campaign against it. It will come up again.
The LV= data was not based only on reporting of collisions but also on a YouGov survey with additional inferences. The CTC has asked LV= to provide its actual data so that it can be examined properly, but as far as I'm aware LV= haven't done that yet. As it is, as far as anyone can tell, the data is of very dubious value.
Cycling organisations are actually very much in favour of accurate levels of reporting. We want to know what really goes on so that we can tell the Government what it should be addressing by its policy. This will be higher than the current official reported figures, but it is unlikely to be 9.25 times higher, as the LV= figures apparently are.
Fight the power Ollie !