Business/Management UG degree + work exp. + MBA or non-business UG + MiM?

Hi everyone, I recently finished High school in the UK; 'A' levels in hand, currently embarking on a gap year, I'm just finishing off my university applications. Initially I was certain on my plan to get a business/management ug degree, work for 3-4 yrs at an IB or a Management consultancy, maybe in a corporate then MBA in the states and spend the rest of my career in IBanking. I've got my applications for Business/management UG degrees ready, and I'm applying to some pretty respectable unis (St Andrew's, WBS, Cass, Manchester and Nottingham (might replace the latter with Lancaster)). However, recently, I met with a family friend who's an associate at Parthenon-EY in London, he did a languages degree followed by a MiM at Imperial and couldn't stop going on about how good the MiM program was. It got me thinking that maybe I should restructure my uni applications to follow a similar route he did. Would it provide a quicker route into senior positions at IBs or Management consultancies? What are your opinions on MiM programs for breaking into IBanking/consultancy/the corporate world? Should I stick with my original plan or get a non-business UG, followed by an immediate MiM and scrap my plans for an MBA?