i've heard nothing but good things about those re-trims, but they don't have an exact leather feel, but are damn close. They should be pretty easy to fit. I think the hardest part would be getting the seats off, and thats pretty easy anyway.
For genuine holden leather seats, it gets pricey, usually from the 1500, to the 2000 mark. Mine are genuine holden leather also, but the bottom of drivers seat is worn, there are a few marks on the back seats etc. Doesn't bother me that much because it's so comfortable, but i would love to get them all fixed up. So it ended up costing me 800 for all the seats, all 4 door trims and all 4 chrome door handles. So i figured it was pretty good value.
If you want genuine though, it might be worth asking a few wreckers, and or getting them to call their contacts to see if they can get anything in with leather.