Just browsing through (think of chopping in the wife's
Mk1 Leon for an 85k miles 2.0 TDi Altea Sport - so looking for potential Altea specific problems) I run an Octavia Scout so pretty familiar with the 2.0PD and what issues to look for (DMF, Exhaust Gas Sensor, Teves MK60, etc) - sorry digressing...
Anyway, if there's still snow and ice where you live there's an easy test to check that the Haldex is working (esp on "summer" tyres). Give the throttle a good hard, hamfisted prod whilst already moving up an icy/snowy hill at a steady speed!
I have found that as power is transferred to the rear following the induced wheelspin at the front, the back end "steps out" momentarily before coming back in line.
Certainly last winter on summers the Scout didn't ever get stuck, though I'd be lying if there wasn't the odd moment of wheel spin. Now on winters the Haldex only has to kick in if it's really serious!!
If the budget could be expanded I'd love to get a Freetrack to go with the Scout, would stop my car getting "borrowed" every time the snow dumps on us.......
Still, a regular Altea on suitable winters would be good enough for her!!