Upvote:2
You can compare ventilators to cars. They are complex machinery that have undergone significant evolution since they first appeared, they need considerable safety margins*,, and require considerable training to use them safely. The price is also similar to a car.
If a company that has no experience in this field would promise to build thousands of these things within a few months, I'd be very careful before buying one. Except in absolute emergencies. Given that it has turned out that the bottlenecks for the treatment of Covid patients are elsewhere (qualified staff, and unfortunately in some places oxygene and even sedatives), my guess is that no sane health official would buy any surplus devices from Dyson. Of course that does not yet mean that really none were sold.
So this question may really be better suited to Sceptics.SE
*Re. necessary safety margins, see e.g. this tragic incident.