Does this sentence sound natural?
I hope I shed light on the suggestion I have just mentioned. (to mean I hope I clarified my suggestions very well)
I wish I had better English, but I work hard to improve it. I'm studying for IGCSE, so I'm only interested in BrE.
No - mention/suggestion is a very odd collocation, and what you hope is that you have shed light (which is itself a bit quaint).
'I hope I've clarified my suggestion' would do it.