>Alan, I've noticed the new common-rail diesels have a characteristic clatter at idle. Quiet, but different from a petrol engine. Does yours do that?

I think every diesel clatters a bit when idling - don't know what makes it do so, but I guess it's just that it's idling at lower RPM than your gas engine. I never had one, but drove half a dozen of them in the nineties, mostly office cars. A friend of mine claims 3.7 l/100km in his Peugeot (304D, I think). Sort of "don't forget to remove the spider web around the tank top before fueling". Nope, tank top is something to wear. Tank cork? Never saw one made of cork. The whatever you use to close the tank intake tube, OK?