If its the bubble roof 61 plate check the scuttle panel under the windscreen has been sealed and the timing chain has been replaced at 100,000 miles. My timing chain snapped in Nov 2019 @ 78,000 miles. Injectors were seized in due to water ingress due to the above fault and had to be milled out. Full top end engine rebuild inc 5 bent valves. Took 6 weeks to repair at a cost of 3.5k (Almost t
he value of the van at the time)
Have a look on youtube, Watchdog did a feature as it also affects the Vauxhall and Nissan models also. The manufacturers stated the issue only affected models up to 2010 that information was incorrect and a lot of late model vehicles are being scrapped as a result of this defect.
Unfortunately its a sellers market for vans due to supply issues of new vehicles but if the mileage is over 100k with no history and multiple previous owners walk away.