Worth it to make an application for neuroscience masters at Oxford?

Hi guys!

I was wondering whether anyone here has studied/is applying/or knows about making an application to Oxford for a neuroscience or oncology masters?

I am graduating from the University of essex (not such an acclaimed uni I know) in mid july with a First Class Honours degree including a year abroad at Monash university, Australia.

I now plan to take a year out now to work in real life setting in a lab.
During my year abroad i also undertook a research project at Monash BDI, which is one of the largest biomedical research institutes in Australia.

I am also currently looking for more research graduate internships that offer chances for "getting published" to add this to strengthen my application for neuroscience or oncology (yet to make my mind) at Oxford that I plan to make in 1 years time.
Bear in mind, I made an application for undergrad but got rejected although I did get into a small residential programme offered to highschool students in the past.

Now this is my query - A-levels was a rough time for me. I was diagnosed with a rare painful neurological disorder for where I had to undergo radiosurgery and was in chronic pain every day and night with the worst of paralysing misery. It was very bad. From predicted As and A*s, I achieved Cs. To be honest staff at school were still surprised since my attendance in the medical room was greater than in any class during those 2 years, but of course these grades are still in the books right?

My question is, what do you think are the chances of me getting into the described programme I wish to apply to?
Does my current and near-future plans make it a potential application? and/or, will my past grades back in sixth-form make me completely unsuccessful.

I know the institution admits students on the basis of "academic excellence" but there is clearly a large gap in my records.
What do you think is the likelihood?
and is there anything I can do to make it up?

Any Oxford postgraduates too - please help me out and let me know if you think there was anything in particular that helped boost your application OR was it just purely 4 A*s and a first class degree?

Thank you!