In reply to idiotproof (Buxton MC):
My advice would be to first invest in things that make any thief walk on by. Doors, hinges, windows, roof, CCTV, alarm, lights etc.
If your thief is inside with no need to rush, it doesn't really matter what you've locked your bikes with. If experienced and tooled up, they'll get your bikes. If idiots, they'll cause a lot of damage. Either way, you'll have a mess of building damage and bike claims to make affecting your insurance for some time. Spend money on deterrence first!