Bougainvilla in Conservatory

We have bought a house with a large conservatory (used to be a swimming pool!) with pots of bougainvilla growing up to the roof trusses. Do I need to cut them back? Most are still flowering though at least one has been affected by some white dusty stuff which now seems to have gone (I sprayed it with washing up liquid on advice!),

 

The white dusty stuff, was probably mildew it might come back, if so spray with a fungicide.
I would wait and cut back in spring, how hard depends on how much space you have. Cut hard and you will probably get fast new growth at the expence of flowers.

pete2255