The key to reducing condensation in your conservatory is ventillation. Ok, at this time of year you are not going to leave the French doors wide open for obvious reasons.
However, you can certainly ease the situation by using the night vent facility on your opening windows. All Prior self build conservatories have this on the opening windows.Just press the window lock button to open the window and move the sash out by about 8mm. Then lock the window in the slightly open position. This is perfectly secure and will provide a gentle flow of air around the conservatory thus removing the moist air slowly but all of the time.
You will not freeze and the humidity levels will be reduced to a more reasonable level. Also leave the heating on low at al times.