Cycle heaven didn't charge me for the replacement fork or labour (which is decent) and have sent it back to Gazelle for investigation as they said its the second one they have had this month.
The also mentioned I might have spotted it if I cleaned it more often. Thing is it stays pretty clean (due to: full mudguards, enclosed drive train, hub brakes and gears, skirt guards) and its the one bike I though of as built like a tank and doesn't do anything other than a two mile commute. Also its not as if I am heavy at 147lb.
So remember to clean and inspect your tanks too.
Originally it was a Police bike that was resold by Cycle Heaven. I have had it just over three years.