My caveat about using historians' names is always that it can seem to the reader that you are 'hiding' behind an established viewpoint.Examiners are always looking for that 'independent judgement' that makes what could be a mid-range answer into a Level 4 or even Level 5 answer (based off AQA mark scheme). By all means, use the arguments of historians but always remember to base those arguments on the evidence you have to hand and not the reputation of whomever you namedrop. Personalising the judgements of historians to your own prose style and understanding of the evidence is a lot more convincing than just 'X says...'.Of course, another facet of a good essay is to show awareness of the historical debates about the topic you're being asked about. Here it can be useful to succinctly lay out an historian's argument with their name attached to prove you've done your research into that area. My general rule of thumb though is to only name historians if I disagree with them and have an example to hand, or I wish to take their general argument and apply it synoptically to a case study they haven't discussed themselves. If you have nothing to add to or detract from historians' arguments I would not bother naming them: otherwise the course of the essay can sink into simple description which wins no kudos from the examiners and hinders the development of a coherent argument within the essay.