I had a 2006 Citroen C3 diesel. Even with the air con on full whack, I could get 64mpg out of it on an average ~60mph journey. In London traffic, I got 52mpg out of it.
I now have a 2006 Fiat Doblo 1.3 diesel van/people carrier. This is a much larger vehicle but it's genuinely hard not to get at least 46mpg out of it with 5 people and a load of crap in it. On my own, 58mpg.
The latter had a timing chain replaced for around £500 but apart from consumables, no problems in several years.
I really don't get it when I see someone in a Dodge Ram (suddenly become popular in the UK?!?) hammering it up the motorways with no load or passengers.