Wow, I didn't even know any of this in the first place. The three inherit titles but are not in line to the succession, it seems, although if they were they would be after his older children and grandchildren and so it would have been pointless to put them in anyway, as it would have been unlikely they would even inherit.
I think this is one of the only instances a claim to royal paternity has been confirmed with DNA to be true. And who would have thought it would be an 18 year old schoolboy who would start this whole thing!