Oversimplifying matters somewhat, but there are essentially 3 different series of DV6 units.
The original from 2002-2009 is the worst, although when once considers the sheer numbers sold the myth is much worse than reality. Myself and Mrs D had three Pugs with this version over the years with nary a fault.
The second series, 2009-2016, lots of minor tweaks and a consequential improvement in economy and reliability.
The engine in our man's van is a redisgn of the DV that arrived in 2016. Same bore and stroke ae the old DV, but pretty much everything else significantly different, a complete redisgn from the block up. PSA would (or more correctly Ford, who had taken over engine manufsdture of the DV series in full by then) have been justified in changing the name of the engine series entirely as everything is different.
This final redisign of the 1.6 - 120BHP and 300NM in output desipte losing a camshaft and 8 vales in the redisgn - was never used by Volvo, who had used the earlier 16 valve 110/112 BHP DV family. It is really a completely different unit to that which went before it and is much favoured by PSA buyers in the know.
The last throw of the dice was not the DV6 at all, but the DV5, yet another significant redesign, this time with a yet another new block as well so physically no relation to the previous DV series at all. Slight drop in capacity is favourable for taxation in certain markets and reduces emissions slightly, albeit at the expense of a drop in power.