No! Both the Villa and the Weekend are designed to be completely odour free in day to day operation. If you detect any bad smells in or around the toilet, firstly check that the fan is operating correctly and that there are no obstructions where the vent comes out of the building.
The most common reason people get foul smells is where you are have been sharing the soak-away pit for urine with other grey water (such as sinks, baths and showers). It’s best to have a small, dedicated soak-away pit for the urine from toilet, but where this is not possible, and smells are detected, the solution is to fit an in-line trap to the urine pipe.
If you are using standard rigid pipework, look at products such as the HepVO inline trap.