Someone broke into my lock up an Saturday night and stole a couple of BMXs. I've had it almost 3 years and this is the first sniff of bother so doing better than expected. They basically made a hole in the door with a hammer and screwdriver then made a mess of it with bolt cutters (which oddly they left behind) in order to get to the mechanism.
Is there any realistic way of making these doors more secure? I can't bolt anything into the floor in front of the door as it's gravel (unless I put some concrete down).
Everything i've looked at so far that I can fix to the top/sides doesn't look like it would put off anyone determined to get in get in.