  Due to improvements in computer performance and algorithms, the rapidly
increasing cost for unquenched Wilson-type fermions with lighter quarks has
been ameliorated and new simulations are now possible. Here we present results
using two flavours of O(a)-improved Wilson fermions for meson decay constants
at pseudoscalar masses down to 320MeV. Results are at several lattice spacings
down to about 0.07fm and include a non-perturbative determination of the
renormalisation constant. This enables us to attempt contact with (partially
quenched) chiral perturbation theory.
