HELP please- graduate entry previous degrees

Universities are very different in their requirements for grad entry. Imperial for example has a set list for what it expects from your previous degree whereas St George's will accept any degree even arts degree if you sit the GAMSAT. You need to look at the unis that you are interested in and check what their requirements are. If you want to be safe and have maximum options you can pick something like Biochemistry, Physiology, Biomedical sciences... Neuroscience is accepted by many Unis but you still have to check as it is a fairly specialist degree and some unis may want you to have a more well-rounded scientific knowledge than that. Also don't pick a degree based on its title, make sure you research what it actually entails and whether you can commit to it for 3 years... Why don't you take a year to finish your Chemistry A level?

You can apply to GEM with a degree in any discipline.
I'm applying once I've graduated in Law. Because it isn't a science degree, my options are limited, but those two should give a much wider scope.

Really? What made you want to change to something so different?