May I ask why you consider HRH Prince Dipangkorn Rasmijoti Maha Vajirojtamangkun Sirivibulyarajakumar to be the heir presumptive to the throne of Thailand?

My understanding is that the Monarch is empowered to appoint his/her heir and that, should a monarch die without having done so, the Crown Council is empowered to select a successor. In this system, therefore, there is no place for an "heir presumptive" - either there is an acknowledged heir or there is not. And at the moment there is not.

The young prince's chances of being nominated are complicated by his having two older half-sisters and five older (exiled) half-brothers, not to mention a widely-venerated aunt.