Had my best ever bike nicked from a shed. (OK it was 1974)
I've only once kept a bike in a shed since, but have had other things in sheds, garden tools, lawnmowers etc.
I fit alarms to sheds and garages. Very loud ones. You can buy them or design one and fit it, or if you don't know how to do it yourself pay a trusted friend to . Those alarm mines are ideal as well. I also fit alarms to bikes (see
ebay, or you can put an alarm padlock on them)
Unfortunately it's illegal to go any further!
Good advice to try to go for more than 6 feet long. 2 metres or 7 feet are needed to really be able to use it easily.