6k sounds about right. I had a D5 V50 with a problem no-one could diagnose but in the end the consensus was "something internal". Other than a Volvo dealer nobody recommended tearing it right down to fully diagnose and fix it because it wouldn't be cost effective.
Most suggested just trading it and moving on (which I ultimately did). Berry would do a swap if they could get a good used engine and it would have been 6-7k.
D5s seem to me to be hit and miss - lots go long distances but some fall over early, At the same time I was trying to get mine sorted there was another D5 V50 at Voldat that had dropped its bottom end. Mine was 69k, that one was in the 50s. I suspect lots of town use is part of the problem (as for all diesels). Berry also seemed to have a regular trade in selling engine swapped D5s of various configs (like XC60s).