It IS a defence for the person to prove that the circumstances were such that there was no likelihood of their driving when the proportion of alcohol in their blood, breath or urine was likely to be above the prescribed limit.( 'Circumstances' excludes injury to the person or damage to the vehicle as a result of an accident involving the vehicle).
Common sense has to be applied. If I left my only car keys with a credible landlord under strict instructions that they were not to be returned to me until I could not possibly be over the limit then I'd expect to be able to prove the defence. The court might think that my removing the battery or a wheel was a cosmetic exercise or ineffectual in that they'd not believe that I would not drive at a time when over the limit.If my reading was very high it would be many hours before I was below the limit.In the instant case, the court is almost sure to wonder why the man was staying to sleep in the van if he'd no intention of driving it in when he woke up in the morning, or as soon as he felt better, and conclude that then he was likely to still be over !.