Hi Ta - I'd already looked there - but I can get a 2nd hand G29 for about £100 - so that's a little on the pricey side - was hoping for a second hand one!
With gear like this "SimLab GT1 Rig, Fanatec DD1 Wheel, Heusinkveld Sprint Pedals, TH8RS shifter, Buttonbox, Handbrake. All the gear, still can't drive for toffee though ! ", the Drivehub is a minor investment. You could also play GT6 on PS3 if you wanted to.
My drive hub was one of the cheapest "upgrades" I've done in a while. You can't compare a cheap logitech with a Fanatec rig, even the older cheaper ones. Even just the load cell is enough to warrant a drive hub. The only obvious upgrade is the CLS Elite for Playstation and a load cell based brake.