  We have followed up the three Y0 dwarfs WISEPA J041022.71+150248.5, WISEPA
J173835.53+273258.9 and WISEPC J205628.90+145953.3 using the UKIRT/WFCAM
telescope/instruments. We find parallaxes that are more consistent and accurate
than previously published values. We estimate absolute magnitudes in
photometric pass-bands from $Y$ to $W3$ and find them to be consistent between
the three Y0 dwarfs indicating the inherent cosmic absolute magnitude spread of
these objects is small. We examine the MKO $J$ magnitudes over the four year
time line and find small but significant monotonic variations. Finally we
estimate physical parameters from a comparison of spectra and parallax to
equilibrium and non-equilibrium models finding values consistent with solar
metallicity, an effective temperature of 450-475\,K and log~g of 4.0-4.5.
