Hi there!
I would definitely consider taking English Literature seeing as you were already going to take Literature and Language, unless you particularly wanted to take English Language as well. Personally, I found English Literature very facilitating and although taking it at A-Level is definitely a massive step up from GCSE, with some determination it is fairly easy to adjust to once you master the assessment objectives.
As for Sociology I think this would also be a good subject that compliments your Psychology A-Level quite nicely. In my year, Sociology was a very popular subject and the majority thoroughly enjoyed it. It is a shame that History is no longer being offered but if you want to be a clinical psychologist then I, personally, don't see it as a necessary subject to have in order to undertake your future degree.
I think that English Literature, Psychology and Sociology is a nice combination of subjects to have. My only point would be to consider that both Psychology and Sociology are typically 'new' subjects that you can study at A-Level that you may not have studied at GCSE. This means that you don't already know whether you will enjoy these new subjects but I wouldn't worry about that too much unless you are completely happy to take them.
If you did decide to take History and English Literature and Language, are there other colleges near you that will be able to provide them?