LSE - Columbia Dual Degree (MPA) chances??

I'm finishing up a master's at a similar program (got into SIPA as well). Also interviewed for some of these macro research type roles but heading to another field.

SIPA is a cash cow in the sense that they won't give you any grant aid coming straight from undergrad IF you get in (which is also tougher without experience). Once you're there, you will most likely use separate career services from the MBA / other schools, and they're likely subpar for finance careers given the school's focus. If you're crafty, you'll still be able to take advantage of some on-campus events, and having Columbia on your resume absolutely goes a long way (people outside of Columbia don't generally have a mental hierarchy of the "prestige" factor associated with each school. Assume this goes double for London).

There are definitely some macro-research roles looking to recruit students from programs like this, and your alumni network will be the primary path to the banking gigs. I interviewed for buy-side roles and found that the shops weren't quite sure what to do with me. In one case, I did four interviews at a prop shop only to be told my math background wasn't sufficient (the last round was a pure fit interview, so imagine my surprise). 

The main thing you should be asking is whether its worth it to drop a massive amount of cash on this program, again assuming you get in. You better know that you love international finance.