He is, according to his agent, "Genuine, laidback & sincere with a gritty, warm, reliable and affectionate voice":
https://qvoice.co.uk/voice-artists/index.php?profile=paul-barber
(One would have hoped though that his agent would know that the character he played in Only Fools and Horses was called Denzil, and not Delroy!).
I've not seen the series but, having just taken a look at a clip on YouTube, I can see why you find his narration irritating. It reminds me of a young child, reading from a story book, who's not yet learned exactly where the stress should go on each word:
How many more series about bailiffs can there be? I'd have thought that the numerous 'substantial damages' C5 has had to pay for invasion of privacy during episodes of Can't Pay We'll Take It Away would have been the end of them.