Conclusion: the oil pump vanos solenoid was causing maximum oil pressure to go to exhaust camshaft, which made it stick in full advance position (could not return itself). This video shows me examine the problem, before I knew it was the oil pump vanos that was the problem.
After changing the timing chain kit I had problem with exhaust camshaft getting locked in wrong position. I replaced the camshaft sprockets with new ones (did it twice for exhaust!) but still problem persisted. Changed inlet and exhaust vanos solenoids still persisted.
Exhaust vanos solenoid (in sump) was faulty (no error code) Oil pressure was too high (10bar on code reader, maybe bit inaccurate as should use mechanical oil pressure tester). Replaced oil pump vanos solenoid with new and problem solved. Pics at beginning show exhaust camshaft locked in wrong position. Driveshaft has to come off for access to replace it, not fun.