The link between English Language is most likely referencing the fact that both involve an analysis of sources (text in the case of English Language, but for A-level history this is primarily the medium through which sources are presented) and language, and that both also require a good ability to write (which is essential for essay based subjects, of course).
I believe that, with a proficiency for writing (and analysing language), as (perhaps) evidenced in a potential A* in English Language, History as a subject shouldn't be too difficult to pick up. Of course, History is a distinct subject; there are skills in History which are not required in English Language. You will, for instance, have to compare the relative significance of individuals, events and factors, and to do this well you will have to use links between such 'things'. I don't think this is too difficult, again, with some prior experience (and skill) with an analysis based subject such as English Language (and others, perhaps) to attain.
I'd say, therefore, to give it a shot, if it is something that interests you. I would recommend talking to a sixth form teacher if at all possible, though I'm sure advice presented on here will also be of use.