Are iGCSE's equivalent to GCSE's Watch
As I want to do Medecine!!
My year had regular GCSEs and the year below, now that my school has academy status and freedom with exams, are sitting science IGCSEs. In my opinion, the ICGSEs seem to be much harder that GCSEs as a lot of the content is similar to Unit 1 of AS! However there is a lot less How science works crap questions and more focus on the science aspects. The argument from my school is that students will be better prepared and less stressed at AS which is very true but the downside is that if you do not plan to take science forward from GCSE it will be a pain and a lot of work in comparison. This is also true for maths.
I do not know how it would affect English. Try and dig out a copy of the syllabuses and compare the 2 and ask what books you would cover. If you get a choice of books, choose the ones that have the best Sparknotes. They helped me immensely with understanding and analysis at GCSE to the point where I could do it confidently myself and went on to take English Lit AS. Ask your teachers for copies of practice or homework essays from students who got A/A* and study their technique. How do they structure their essays and points and try an mimic that in your writing. Don't spend too long on it though, focus on your AS as they are more important.
IGCSE are significantly harder - it's the whole reason they were developed, to provide a more challenging exam. Not only is the content harder, but it is only terminal exams - not coursework or modules. I did half and half i / GCSE and there's no doubt they were more difficult.
Taking the IGCSE in English would have an advantage over the GCSE in that it is actually easier to prepare for, if not actually easier in and of itself. The textbooks generally have more focus on a development of skills over time rather than a list of prescribed skills you are expected to just absorb through osmosis. Nor would you be hampered by poor controlled assessment performance, which will be holding you back if you decide to sit the GCSE again. It would be a matter of you showing up and sitting the exam and doing your best on the day.
Both exams are given equal weighting by universities so I would recommend you take up whichever option you think will give you the most opportunity to improve your overall grade.