Yes, Grum it is complex but when the people who make up the rules are not even confident in taking someone to court to enforce what they thought it meant it's not a good sign.
It is not that simple, what tends to happen is the commercial world has changed since the rules were originally drafted and a scenario that was not envisaged is the matter of the dispute. Alternatively, the drafters were not aware of how the rules would work when confronted by certain types of transactions.
You then have to add the international dimension, where each country has developed their legislation separately such that two countries may treat the same transaction in a completely different way.
HMRC has quite a few tools to combat tax avoidance thanks to the last and the present governments, and as a result,there has been a substantial reduction in the "industry". However, until there is international co-operation there are always going to be opportunities and to give the present government their due, they are trying to address this.
My educated guess is that Ecclestone planning was premised on the fact that his former wife is a non dom.