Someone BTL pointed out that no official body has announced that he will receive enhanced security; that, if you parse the text of the article, it harks back to announcements made after the 'catastrophic car chase' and probably relates to that dodgy letter.
It was late when I read the article, and I don't have time to re-read the article right now, but the BTL's conclusion that this was an example of Sussex manifesting rang true at the time.
But, to echo others - who else makes such a fuss over how much state protection they're going to get when out and about? Especially when his visits seem to be nothing official, just bread-and-butter visits to organisations he has affiliations with.