Stair gate (Hyde Lea ST17)

I am in need of a stair gate to keep my dog downstairs. He’s almost 14 years old and has arthritis. He loves to get upstairs just to sit in the bedroom window watching the world go by. Trouble is, he has fallen down a couple of times, only a few steps but I’m worried he might hurt himself. So if anyone has a stair gate they no longer need, I would put it to good use. Thanks.