https://biketrac.co.uk/ If the bikes armed and it moves more than a couple of feet you get a call right there and then. You can also view online exact position and even battery voltage. Highly recommended
Ive got Biketrac on all of my bikes, do find after a couple of days if I have forgot to plug in the trickle charger back in from a ride that you get a low battery alert. Would definitely recommend but bike needs to be on a trickle charger otherwise it kills the battery, not a problem if you ride a few times a week, but for me it’s more like once a month
If you have line of sight - I would recommend a high powered hunting rifle..... only joking..... You can get the land mine units - which basically fire blank shotgun cartridges Mount them on the doors and the bike - so that they go off... generally thats enough to keep people away... Then that combined with alarm to your phone - would buy you time. You would need 2 large leisure batteries - one on charge and one in the garage Would support Mini wifi unit and a camera, and a blaster alarm - you would need to mount them up high... As others have said - the fact you have lots of chains will buy you the time to get there after they trip the door... if your home - but if you are away - probably not.... Any reason you have to use a lockup
Smoke bomb from stage supliers about £15. They come in different colours but will all fill the garage so they cant see and attract people who will probably call 999 thinking its a fire.