  We present a detailed photometric study of the central star system of the
planetary nebula Hen 2-11, selected for study because of its low-ionisation
filaments and bipolar morphology - traits which have been strongly linked with
central star binarity. Photometric monitoring with NTT-EFOSC2 reveals a highly
irradiated, double-eclipsing, post-common-envelope system with a period of
0.609 d. Modelling of the lightcurve indicates that the nebular progenitor is
extremely hot, while the secondary in the system is probably a K-type main
sequence star. The chemical composition of the nebula is analysed, showing Hen
2-11 to be a medium-excitation non-Type I nebula. A simple photoionisation
model is constructed determining abundance ratios of C/O and N/O which would be
consistent with the common-envelope cutting short the AGB evolution of the
nebular progenitor.
  The detection of a post-common-envelope binary system at the heart of Hen
2-11 further strengthens the link between binary progeny and the formation of
axisymmetric planetary nebulae with patterns of low-ionisation filaments,
clearly demonstrating their use as morphological indicators of central star
binarity.
