Meanwhile I know that like a Basenji, he should never be off leash, and we always need to make sure the gate is securely shut,
I have had Basenjis for a long, long time now. I have always let them run off lead in the woods away from traffic. They have all been taught - and I have had up to eight at a time although am now down to one, soon to be two (!) - to return to me if I whistle. Basenjis CAN be taught to run free and to obey commands.
Yes, gates should be kept shut, tightly, at all times. But away from traffic, they can be trained to behave and allowed to run free.
I have bought a puppy sling for my new boy so I can take him to the woods with Hoover, and let him meet lots of people and thoroughly socialise until he has had his shots. I don't intend to deprive Hoover of her freedom just because of the puppy. He will learn to walk on a leash but mostly he'll be the hunter nature intended him to be.