Always done this myself, same on building sites, usually night shift guard came on at 4ish so made a point of speaking to him rather then ignoring like every other arrogant site worker!!
Sorry to hear of your loss and damages, bloody nightmare!!
Those nightshift guards aren't all that. Used to have them on my sites and we still had stuff nicked right outside the site office compound! They fall asleep or are constantly waffling on the phone and don't hear a thing until their alarm goes off to do the hourly walk around. Cant blame them because the pay is rubbish.
After all the lead off the dormer windows was stolen for the 3rd consecutive time even with the guard there - we ended up with a right weirdo who was up for the fight and after he chased them off a couple more times they went back to just robbing the site car park instead in the middle of the day.
Those two Hitatchi's in Aldershot look like they were a stolen to order thing especially as they went to such lengths to get the 3t going and they were both pretty new. Taking an 8t isn't opportunistic, you've got to be organised for that.
And realistically guys, those of us thinking we are going to get out of bed and go down there and have some kind of Jackie Chan scene with them are probably deluding ourselves. There's likely to be a few of them with nothing to loose, stolen van, we don't know where they live but they know where we are! Giving it the Hong Kong Phooey at them might scare them off or it might get you stabbed. Even if you took the shotgun out there are you actually going to shoot them? The law just isn't on our side for this one. Tough as we are, its not worth the risk I don't think.
They hate alarms, noise, lights and effort. Give them plenty of that and they will soon scamper when the whole neighbourhood wakes up with spotlights and the foghorn going off. Harder to achieve at our yards I appreciate but the more you do, you might stop the less organised ones at least. The guys who do this professionally you are unlikely to stop lets face it.