  We explore the phase diagram of two flavour QCD at vanishing chemical
potential using dynamical O(a)-improved Wilson quarks. In the approach to the
chiral limit we use lattices with a temporal extent of N_t=16 and spatial
extent L=32,48 and 64 to enable the extrapolation to the thermodynamic limit
with small discretisation effects. In addition to an update on the scans at
constant \kappa, reported earlier, we present first results from scans along
lines of constant physics at a pion mass of 290 MeV. We probe the transition
using the Polyakov loop and the chiral condensate, as well as spectroscopic
observables such as screening masses.
