"actually this ensures that the cabin IS pressurised on landing! It is the opening of the outflow valve that depressurises the cabin."
Correct. That is why the cabin-crew can't open the doors if you forget the FLT-GND switch taxying in. We have all done it, especially on a mixed fleet of CPCS & DCPCS! Cracking your DV window open will assist the process.
S&L