I've owned several vehicles over the years Citroens too but all the VW's gave trouble. The dropped valve was on an air cooled camper van. My Citroens both broke down in the first week from new due to poor electrics.
I've just remembered another VW I owned for about a month - I went to the local garage who specialized in servicing VW's for some parts. When I quoted the engine number they fell about laughing. It was a particular engine that was so bad that the mechanics would mark it with tipex and put bets on as to whether it would get as far as the first service
I don't know where the reputation for the Hiace being a gas guzzler comes from - all the research I did before buying one suggested they were pretty economical (deisel). I've not found it heavy on fuel even on a 500mile return trip to Grimsby.
Amazingly the Fiat Doblo vans seem pretty reliable according to people on this forum who use them - only 1300 deisels engine too.
Most vehicles have an Achilles heel Renaults, Vauxhall and Nissan seemed to have gearbox issues, Transits appear to be rust and injectors. Citroen possibly electrics although I had a Despatch that was problem free.
The VW my son drove was a cracking van bought from new - lasted three years before it was deemed fit for the bin by the main dealers - just made it out of the warranty period.