Big 3 CRA OR non-BB M&A Internship in Central Europe?

Hello! I wanted to ask your advice...

My situation: I am finishing up my masters soon (in a target school in Central Europe, did not work between undergraduate and graduate) and have been applying for tons of jobs during the past 8+ months or so. I was initially hoping to get IBD FT in London, but since my previous internship experience is from the Markets side (and probably for many other reasons...), I was unable to land one. However, I got an offer for an off-cycle (Sep-Nov) M&A internship in one of the top3 banks (non-BB) in the country I am currently based in (think Paris, Frankfurt, Amsterdam, Zurich). For this bank, they hire 100% of their M&A analyst class from previous interns and could keep me on board directly after the internship if I win an offer (around 50% chance based on historical rate). However, I also landed a FT rating analyst role in one of the Big 3 credit rating agencies in London (exact rating team to be determined).

I am having a hard time deciding what to do. The pay in London is almost double, and it is obviously a permanent contract. If I go with the M&A internship, I would need to go through the London recruitment cycle again next autumn alongside with work. This also brings some pressure to finding a job soon after the end of the internship, as I don't want to profile myself as an unemployed graduate who failed to get a return offer. Brexit is also a risk, as I am an EU passport (non-UK) holder. If I'd go with the offer from CRA, I'd already be based in London for networking and interviews. I have also heard that it is possible to move from CRA into BB IBD.

In the long-term, I am planning on exiting and building my own business, and that's why I hope to learn as much as I can in the coming years, network and "get the stamp of approval" on my CV. Personally I'd prefer living in London, as I am from another country and don't know the local language.

Any comments are appreciated!