A-Levels, especially with 'glorious' subjects as your own, is not an easy walk. =P What is your forecast grade for English? If it's an A or A*, then I suppose you're not neck-deep in water. I suggest you go with English Literature; General Paper is also difficult and not considered a real qualification by universities abroad. I can't pinpoint any since I brushed through many, but just google some Ivy League universities and see if there's accreditation for GP.
English Literature is tough and in essence, misery, but if you put your heart to it, it might just work out. So I guess you should go for the stronger, more definite qualification.