I am looking for a substantial sized catio for my Maine Coon boy of 3 years old. Although I intended to let him out the house one day, I never did as I worried he would die on the nearby railway tracks as a previous Maine Coon did, or be stolen. I have eventually decided he can't be inside without stimulation, and want a catio for him to spend the days in safely. I have a concrete patio outside, but in the summer I have an outdoor hot-tub which I keep on there which is 1.8m x 1.8m so either the catio would have to be super large to accommodate both the jacuzzi, the old brick barbecue, pots etc; or I would have to moveable so it would attach to my patio door catflap in the winter, but for several weeks in the winter I would drag it to the lawn area and hopefully attach a mesh run to join it to the door. As this is not a typical setup, I suspect a custom build would make more sense than something off the shelf (I could be wrong though). The concrete area is 487cm wide and 415cm deep, although after a depth of 262cm the width shrinks as it ends in a semi circle. I have attached a photo for illustrative purposes. I live on the Kent / London border so if anyone can give any recommendations I would be obliged. I'd also be interested in good ideas for items to keep him stimulated once there. He does love looking out of open windows and especially bird watching. Thanks for listening.