So Mrs P and I got in a near miss today. We were overtaking a long line of parked HGVs on our nearside (myself in front). Another lorry was approaching us, from beyond the parked lorries, and it flashed its lights. Understandably enough, I took it for a 'come on' gesture seeing as we were already overtaking, and there was scarcely room for the lorry to squeeze past the parked lorries - let alone the parked lorries plus a cyclist.
But it wasn't. It was an invitation for a car driver to pull out of a driveway on our left, just beyond the parked lorries. Completely unsighted and not visible to us, of course. Which she duly did...

Luckily my brakes were good enough to just avoid the inevitable collision.
Who was in the wrong? I did utter a few choice (censored) words targeting the lorry driver, but he probably didn't hear them. Perhaps the headlight flash should have been taken by us as a warning after all?