You can see the top of the bald head of his private bodyguard just behind his shoulder. He probably had other locally hired security too.
Which absolutely means whatever security he has is more than sufficient for him to feel at ease walking down a residential street in London and knocking on random doors looking for his mates.
He doesn't NEED publicly funded armed personal security when he comes to the UK, he just wants it.
RAVEC did their job, they deemed him low risk on this occasion, there are no paparazzi chasing him, no random fans jumping out of the bushes, no taliban or acid attackers or lone actors putting his life at stake, no one even noticed him.
It was a month ago, it's only coming out now, possibly because the papers were doing their due diligence on the veracity of it.