Hi my car unlocks, starts and drives with both fobs, the passenger door lock and middle button work, but both fobs have lost the ability to lock the car, I’ve recently changed the batteries and had no issues for weeks then suddenly neither work. Has anyone had this happen to them or know of a fix for it?

Does the car beep when you try to lock it?

It probably thinks something is open, hood, boot, or maybe one of the door lock mechanisms. Even if closed, if the respective sensor has failed, the car will think it's open.

The hood sensor fails very commonly and is easy to replace, or just bypass.

Not sure if your remote is my 2008 model style or not but, I had a similar issue with one remote I replaced (soldered) lithium batteries on. I ended up having to open it up again and check and re-solder a joint. No similar issue for years since then. If your horn beeps, follow merlinj79 advice.