I finally did the Haldex fluid & filter tonight using genuine stuff.
It wasn't too filthy and there was no 'crud' in the filter, so I'm guessing the previous owner had it done at some stage, it seems like he looked after the car. I've also noticed the front lower control arm bushes are superpro.
I made this tool from a coat hanger to remove the filter.
Now all the fluids except the coolant have been changed, but that looks nice and fresh and I might renew some of the known problematic hoses and do it all then.
I'm starting to really like this car!