10k about right as a starting point
insist on a scan with solus etc-as the heater relay and glowplugs dont fire up a warning light-also use the solus to check it gets up to correct operating temp[well above 70 deg] if it doesnt its likely to need both thermostats done[main one is nippy and an hour and a half work[ish] egr stat-five minutes
there is also a hidden menu on the dash for engine temp[no gauge fitted]

important that a standard car has all glowplugs working and gets up to temp as a faulty glowplug stops the dpf regen and it soots up dpf quick as it runs rich if stats are poor
yes-great cars to drive,335d 6 seconds to 60 standard and nippy top end-bags of grunt,and thats before a remap .....lol