Look, the fact of the matter is that they have no idea if you spent the year diligently being a faithful carer or you decided you couldn't be bothered and spent the year drinking. They want evidence to prove it is the former and not the latter.
You therefore must have some evidence - did you tell your university the reason you left? Do you have any sort of calendar or record of your caring?
You've already stated that while you were "caring" for your grandparents, you were not registered as a carer for your grandparents, so it was not official and you received no government support. Likewise you never spoke to your GP about the difficulties or anything related to that.
I don't wish to be harsh, but ultimately unless you can provide some evidence you were being a carer rather than having a long holiday on a beach, they've zero reason to help you or provide you with anything.
Incidentally, you state you can't afford anything right now - you are aware that even if you get the year refunded you will STILL need to pay the first year right? I.e. you will need to pay £9,000 personally in few months, before you can even get any loans.
I would also note that you do not intend to do the same course, but plan to transfer to a new one which probably doesn't help your case.
I would suggest you review all the evidence you could potentially submit and check whether it is sufficient evidence to meet SFE's criteria. I would also seriously consider whether this is a route you wish to pursue, as from your previous thread it seemed like the primary reason was just to make your parents think more highly of you (and you of yourself) rather than for any practical reason.