In this paper, we analyse the results of experiments performed on the LULI2000 laser facility. Nb and Ta dot targets were heated by up to ∼800 J of 2ω laser light in 1.5 ns pulses. The expanding plasma was characterised by Thomson scattering (TS) of a probe laser beam, and time-integrated L- and M-shell X-ray spectroscopy. The TS probe was operated both during laser operation and after the end of the laser pulse, providing ionisation data near the Ne-like or Ni-like closed shells as well as for the recombining plasma. We give the results of 2D radiative hydrodynamics, non-LTE kinetics calculations and detailed spectroscopy that show a satisfactory agreement between experimental and theoretical data.