Pace,
You're right I didn't know if he had turned, and to be honest I didn't look at the DG upon taking control and immediately descending. I guess it was an act of faith and a feeling my attention had not been diverted for long enough to allow a significant turn and the recency of knowing that my path thru was clear providing I was at or below 1800 as the view thru the pass prior to handing over control was clear all the way thru and beyond at that altitude.