  With the prevalence of wide-field, time-domain photometric sky surveys, the
number of eclipsing white dwarf systems being discovered is increasing
dramatically. An efficient method to follow these up will be key to determining
any population trends and finding any particularly interesting examples. We
demonstrate that multi-band eclipse photometry of binaries containing a white
dwarf and an M~dwarf can be used to determine the masses and temperatures of
the white dwarfs to better than 5 per cent. For the M~dwarfs we measure their
parameters to a precision of better than 6 per cent with the uncertainty
dominated by the intrinsic scatter of the M~dwarf mass-radius relationship.
This precision is better than what can typically be achieved with
low-resolution spectroscopy. The nature of this method means that it will be
applicable to LSST data in the future, enabling direct characterisation without
follow-up spectroscopy. Additionally, we characterise three new
post-common-envelope binaries from their eclipse photometry, finding two
systems containing hot helium-core white dwarfs with low-mass companions (one
near the brown dwarf transition regime) and a possible detached cataclysmic
variable at the lower edge of the period gap.
