Never heard of a folding dog gate

There may be one, but otherwise I got a great dog gate from Argos, you do not need to screw it into the wall, door or banister, it can be stuck on at the top and then screwed in or out to fit, you can very easily remove it again in seconds and pop it back when needed. They are my favourite doggy accessory and solve a multitude of would be problems. :-D