Global Markets Grad at Santander CIB vs Equity Research at RBC

Hey there, I recently received an offer to do Equity Research at RBC this summer in the London office (very happy about it). At the same time, I have an offer to do a 1-year grad scheme at Santander CIB in Madrid (its HQ) within Macro Strategy. I could do the summer + the grad since I wont start the latter until mid to late September, but I also think there's good chances I'll get a return offer from RBC if I do a good job (they only hired 2 interns). 

I like equity research but I don't think I'm passionate about it. On the other hand, the macro strategy role is something I could see myself doing for a long time and I like the fact that the strategists sit right next to the traders. Santander gives me the flexibility to also switch to trading at the end of the grad scheme if I'm interested in it, and I'm pretty sure I want to do markets in the long run. 

However, I understand RBC is a good name and I would also be in London, allowing me to network and meet different people in the industry. But as I said, I don't think I like equity research as much as I like markets. 

If I were to stay in RBC and do equity research for 1 or 2 years, how feasible would it be to transfer from equity research to markets later on? Or should I start at Santander Spain and hope to get transferred to the London office and move from there?