We study ratios of azimuthal-angle distributions in Mueller-Navelet jets after imposing a rapidity veto constraint: the minijet radiation activity is restricted to only allow final-state partons separated at least a distance in rapidity $b$. It is well-known that the asymptotic growth with the rapidity separation of the two tagged jets of the NLLA BFKL Greens function requires a value of $b simeq {cal O} (2)$ in order to avoid unphysical cross sections. We further investigate this point from a phenomenological point of view and work out those values of $b$ which best fit angular distributions measured at the LHC in a realistic set-up where impact factors and parton distribution effects are also taken into account.