G'day Sab,
On our 14ft Cav we remove the annexe walls (if used that trip) & roof the night before we are due to depart. We (wife & self) find it easier to do that way, particularly when having to depart by set times. I also think that the weight of all that canvas would be fairly difficult to fold up on the trailer. We also have a fly over the tent roof which keeps it dry & clean, so wouldn't like folding a wet or dirty annexe roof over it.
Cheers,
The Nats