Aye Ian,
With the advent of battery disc cutters, most physical barriers are not effective. Big padlocks/bars/grills just arouse inquisitive prying. A "Ring" type remote camera, covering both the front and rear of the garage/house, can be hidden and connected either to a smart phone or your home computer, probably produces more useful information and a big LED floodlight, operated by a PIR switch, is likely to make people nervous.
Chaining the bikes together and then to a ground anchor may not stop the theft, but it delays the removal of multiple "sweets" and whilst you may loose a wheel the machines may remain.
Being out in the sticks, loud alarms aren't really much use here and having heard of two bikes stored in Grandfather's garage 2 miles down the road from the owners property, stolen after the thieves kept watch to see where they were kept, came across the fields at the rear of the garage, removed the rear wall and wheeled them back across the field, there appear to be no limits to what some will do, if they are intent on lifting your bike. Camper vans and or their luxury fittings are also now increasingly being targeted, even when locked away in workshops!
As for the CCM, I'm no sure; bit of a "desirable" in many eyes, not mine and insurance will no be "reasonable" after this incident!

Good health, Bill