After serious thinking Dave Plowman (News) wrote :
Seen on TV consumer progs that the common ones (Crocodile?) are rubbish.
;-)

The Crocodile doors are just a standard roller door, sold by many other
suppliers. Difference is, they charge a premium for supply and fit. The
door they supply is exactly the same has my door, which I sourced
direct from the factory and fitted myself - bet I paid one third the
cost of Crocodile's door.