We investigate in scale-invariant B −L scenario where the Standard Model (SM) is supplemented with a dark scalar φ associated with gauge & Yukawa interactions, described by the couplings g BL and y respectively, leading to radiative plateau inflation at scale φ = M in the ultraviolet (UV), while dynamically generating the Electroweak and Seesaw scales á lá Coleman-Weinberg in the infrared (IR). This is particularly achieved implementing threshold correction at an energy scale µ T arising due to the presence of vector-like fermions. We show that implementing the inflationary observables makes the couplings solely dependent on the plateau scale or inflection-point scale M , leaving us with only two independent parameters M and µ T . Within the theoretically consistent parameter space regions defined by m Z BL > 850 GeV, from the assumption of independent evolution of the dark sector couplings from the SM couplings and M < 5.67 times the Planck scale (M P ) required for the realisation of inflationary plateau-like behaviour of the potential around φ = M , we identify the parameter space that is excluded by current LHC results involving searches for the heavy Z BL boson. For typical benchmark points in the viable parameter regions, we estimate the reheating temperature to be ∼ O(T eV ) thus consistent with the standard Big Bang Nucleosynthesis (BBN) constraints. For typical benchmark points (M = 5.67, 1, 0.1 M P ) we predict the scales of inflation to be H inf