As you’re pretty clued up in this purely hypothetical, what about doing this.
The person wanting to give away a large portion of their estate, let’s say it’s someone who has a large amount of cash but rents a house. That person and the person they want to give the money to both register on one of the American Poker sites.
They deposit a grand a time and just play heads up poker against each other (multiple hands both winning some pots) and the recipient wins every time increasing his bank balance exponentially.
They do this until all the money has gone from the giver to the recipient. The poker site will be happy as they get their rake (which means about 5%!of the pot is lost) and I doubt they would give information away to a British authority, am I missing something?