Population synthesis models indicate that the age of LBDS 53W091 is in the range from 1 to 2 Gyr and depends on the specific model.
Older ages require sub-solar metallicity models.
The estimates of the age of M32 range from 3 to 5 Gyr and depend not only on the model but also on the SED of this galaxy used in the fits. Contrary to the assumption by Dunlop et al. The contribution of the lower MS to the UV flux at these wavelengths is non-negligible at the ages of interest. This explains the difference in our age estimate of LBDS 53W091 and the value of 3.5 Gyr found by Dunlop et al.