Hey there!
I have been bothered with this question for some time. I am holding a Master’s Degree in Finance from a good University, having studied in Spain, Germany and the UK, worked for some good well-known banks in Luxembourg and Germany but could not kick start my career until yet. (Well, salary is good... but nothing extraordinary ;-) )
So, I am wondering if I should apply for some good Business Schools in the UK or France... and doing an MBA. Is 30 too old? I don't think that i will get a job in Consultancy or IB with 30 + afterwards… And if I "invest" 40 k to 70 k Euros... I am not sure if I will get a positive NPV...

Of course you will. 30 is the average age on most top European MBA, and you can double your salary.

Of course you will. 30 is the average age on most top European MBA, and you can double your salary.

Yes, look at these schools:

LBS: average age 28.6
INSEAD: average age 29
HEC Paris: average age 30

Your quant background and international experience in banking will look good to IBs.