Not really a solution, but even I can't use a garage down here (not sure I want to leave it somewhere else even in a garage as I don't trust the low lifes noticing me pulling her in and out all the time to do work - they can then come back to a deserted garage complex and work their merry charm on the naff garage locks.
It's always a compromise between security and bringing attention to a lockup. Having been 'around' some less than pleasant characters in my youth, I can vouch for how their small brains work, and this is one of those cases where less attention is best.
My old 912 is parked outside the house, sandwiched between a wall and our 'family' car with a tarpaulin over her (and as many shoe box silica sachets as I can find inside the 'cabin' to keep the moisture down as much as possible.
Tarpaulins are good as there is no tempting visuals to lure the nasty rock creatures out with their slide hammers and screwdrivers, and they have to battle with the tarp before they can get at your baby ...

- most won't bother (famous last words)
(PS - on Sunday morning around 3 am we had our old A reg cavalier CD windscreen rubber cut by Stanley and his knife, as they tried to remove the windscreen, they cracked it !!!!!, so they moved on to the neighbours cavalier and took his with the tax disk and a few glasses and bits from inside - may their cavalier rot overnight and leave them with just the windscreen they nicked!)
2 pence worth (memories of youf!) argghhhhhh - my sympathy Oli