I would recommend beefing up the door security if it's an up and over as well.
The main issue is the lock, as it uses a very simple key. Try getting an additional hasp lock, or a shoot bolt.
I've got a big ground anchor that the best bike is bolted to, then two other bikes are chained and d-locked via the main anchor.
Bikes on the wall are secured with a cable system (i.e. lower value bikes/ones that can be replaced).
I blew a drill up fitting the main anchor - needed to go down over 6" into solid concrete, took ages. I then realised the builders had made a very good 'floor' in the garage.