I'm still researching my security options and browsing assorted painful deterrents

Been looking at bolt croppers, for £100 you can buy a set that'll cut straight though 13mm High tensile and 19mm steel ! This is what I'm up against.
So, a combination of wood, metal, noise, lighting, nails, glass, razor blades and a sprinkling of novelty sprung-loaded chav-traps should do for starters.
I still think the best way to go is to prevent the thief from seeing the security one has in place, this way, they can't do a reccy and return tooled up at a later time.