You can make uncomplimentary references to anyone, but keep it proportionate and don't get into personal attaacks.
Paul Hollywood is a gifted and experienced baker and a canny businessman with nice eyes; he also IMO puts too much salt in his recipes and uses a lot of hair product and I don't understand how someone whose job relies so heavily on a subtle sense of taste gets away with smoking a lot (assuming that my information is correct).
Ruby has a huge natural talent for baking and is a really striking young woman with lovely hair
; she also IMO has a habit of making over-dramatic self-deprecating remarks and getting in a tizzy over nothing, and her presentation skills could be better.
I don't think either of them is a terrible person and I am aware that my perception is filtered through heavily edited television and/or impressions filtered back through a long chain of people.