Hi welcome. Yes real World conditions are very different, almost impossible to replicate perfect conditions on normal public roads without causing a tailback! Having said that, if you read the other thread about the MPG Marathon, there are lots of cars getting upwards of 90 mpg on public roads, although it's difficult to find any clues as to how they were driving.
There is also another topic floating around somewhere about the Honda long term economy test.
Citroen and Peugeot share almost everything, so there should be an equivalent version with that engine.
Edit: Just checked, yea the BlueHDi can be had in many Citroens including the Cactus, C3, C4 etc. Fuel figures in the C3 are almost identical to the Pug, so that's your best bet (although I love the quirky Cactus myself!)