Ultimately if they want your bike they will find a way but it’s about making it tricky for them. what I have done is:
1. shed alarm that sounds in the house
2. I’ve built a metal frame that the bike sits and is then locked in by removable posts, these have steel mesh over them meaning that the whole lot has to be cut off not just a section.
3. fitted a kitchen worktop on top of the frame to let me store stuff above it so more chance of making noise and also prevents access from above the bike.
4. massive chain, and lock going into a ground anchor.
the shed sits on a concrete base so the frame is rawl bolted into this and its all welded, the shed could fall down but the frame would stand independently.
So they have to cut the frame and remove the posts before they can get access to the chain and lock then they have to work on that, all the time my alarm is going off and I’m putting shorts on and getting the pepper spray from my cupboard 😀