I'm not convinced that is a scam?
These hydrogen fueled ones are starting to be done, its not true hydrogen, its HHO or "Browns gas"
Some people are convinced they work, some think its rubbish, but whatever you think it doesn't make the vehicle a scam?
The seller is saying cash on collecton, so its not as though he's insisting on cash up front?
I wouldn't buy it, but thats becaue its far too expensive, list price is about £1500!