Advice on best way to switch from medicine to investment banking

Hi,

I'm currently studying medicine at a UK med school. I grew up not knowing anything about finance or IB or other city careers and I've became really interested in pursuing something finance related like IB. 

I'm looking for advice on the best way to try and get into IB. My A-level grades are very good, so I am quite confident I could apply and get an offer from a target to study a science degree. I missed the UCAS deadline for this year, so I would need to apply next year.

In medicine you also get to do something called an intercalated degree, which is basically where you take a year out and study something else and get a degree out of it (it's compulsory at my uni). 

This would mean I would get a degree from a target university, but I'm unsure how this would be received by IBs. I also don't have any finance internships or work experience. 

I'm looking for advice on if I go to a target next year, is it worth aggressively networking and applying for summer internships (planning on doing that anyway), how likely am I to be successful? Or would I be best placed to just apply again for a science degree bsc at a target next year and go from there. 

Thanks in advance.