I'll cut my old nav light open once I've got the replacements fitted. It'll be interesting to see what failed, whether it was the diodes or the board they're fixed to. It was suprisingly dim in comparison to the working port lamp, and even though 2 of the 3 LED's had failed it seemed far less than 1/3 bright.
If the Hella response is anything to go by, they did state that the new models were of a much better quality
. Perhaps they know that their old versions weren't so great which was why they were quick to offer a no quibble free set.
If my lights failed on passage, I actually wouldn't be that worried. I've yet to cross the shipping lanes or any really busy area at night. Interestingly, although they are rated to 2nm and look pretty bright close up, they are not particularly visible from that kind of distance. I've been watched from shore by my parents, and at dusk the boat was in sight almost before the lights became visible.