I want a panic push bar for a single timber door, but we also require to gain access from the outside using a lock with key. What do you recommend?

Depending on the answer to this question; Do you want the door to lock behind you, after you’ve entered with the key OR do you want to have to re-lock it with the key?  If you want it lock automatically, then we’d recommend an Exidor 305 mortice operator, which comes with a euro cylinder & escutcheon for the outside.  If you want to re-lock it with the key, we’d recommend the Exidor 296 push bar and an Exidor 302EC outside access device.