Safety gate to fit narrow door frame

[Bluesea14]

Hi, can anyone recommend a stair gate fit a narrow door frame? It's not the length of the stair gate that's the issue it's width the door frame that it will be against. Most of the plugs on the pressure gates on Argos are 4 cm but our door frame is just 3 cm.

Wall cups not plugs*

If you don't get a pressure fit one, you can get something that will mount on the front of the doorframe instead of on the inside, e.g. the Lascal Kiddyguard.