Glyn, I've had two new factory fresh Eriba's 2007 and 2017. Each needed fettling, the 2007 for 6 months and the 2017 for 18+ months.
At the time it is a pain, but the reality is owners of white wobbly boxes seem to have to continue with the fettling throughout the life of there vans.
My top tip for you is keep an eye on the top lockers for screws coming loose. If you even suspect it get the locker flap off, re-countersink the hinges and re-fix with slightly longer screws of the same gauge with a spot of pva in the screw holes. Some use araldite but pva is fine.
Colin