i mean, no one can really tell you what to do - its your decision.
But i would say, given that you have an apprenticeships (i assume based on what youve said), that you might as well go ahead with that, i think employers would look at it as 'you got a B in economics, good you want to work in finance, youve done an apprenticeship in finance/accounting and have good experience and references, good you want to work in finance'. i really dont think a D in politics, when thats not your future career, is going to be seen as a huge factor in employment possibilities.