I watched it. It IS a spin-off from Death in Paradise. D.I.P. WAS a good show however in my opinion the last few series have been below par. They are trying to get too much out of it and as a result the story is being lost. Still a MUCH better show than most of the Krapp that is on these days.
Beyond Paradise is an attempt to capitalise on one of D.I.P.'s favourite characters and while OK there is no real "feeling" for any of the characters and so is sadly lacking one of the main elements of such a show. (That is putting aside my professional assessment of the preposterous staffing arrangements at both police stations!)
BTW BOTH shows are returning for a new season.
If you like this style of show, may I recommend the Madame Blanc mysteries? 2 series so far and another in the works.