  We present results from a circular polarimetric survey of candidate detached
magnetic white dwarf - M dwarf binaries obtained using the Nordic Optical
Telescope, La Palma. We obtained phase resolved spectropolarimetry and imaging
polarimetry of seven systems, five of which show clearly variable circular
polarisation. The data indicate that these targets have white dwarfs with
magnetic field strengths > 80 MG. Our study reveals that cyclotron emission can
dominate the optical luminosity at wavelengths corresponding to the cyclotron
emission harmonics, even in systems where the white dwarfs are only
wind-accreting. This implies that a very significant fraction of the the
stellar wind of the companion star is captured by the magnetic white dwarf
reducing the magnetic braking in pre-CVs. Furthermore, the polarimetric
confirmation of several detached, wind-accreting magnetic systems provides
observational constraints on the models of magnetic CV evolution and white
dwarf magnetic field generation. We also find that the white dwarf magnetic
field configuration in at least two of these systems appears to be very
complex.
