Front wheel bearing

[albion.rover]

So after having a second wheel bearing disintegrating within 6 months, I decided it's more prudent to invest in a genuine ford part and not give any more moneyou to euro car parts. I don't use my van for heaby work and do relatively few miles but that doesn't seem to make any difference.
I followed the instructions to the Haynes guide and tighten the centre hub nut to an initial torque then rotate the wheel 5 times and the torque it to 420. Seems massive amount of torque and was thinking it was too excessive.
Anyone else had any issues with bearings going back to back?