Hey, wanted to update this as I am now sitting in ICN awaiting a (delayed) flight back to the states.
So my hotel in Beijing called the police who stated that it was “not a problem, and everything was electronic anyway”. Not sure quite how to take this statement I gave myself plenty of time when I went to PEK for my flight to DYG if I had any issues. No problems in PEK, and none departing DYG for XIY either. To be honest I would never have spotted anything if it hadn’t been mentioned at the first hotel as it was never brought up again.
On departure from XIY this morning I got held up about 15 minutes because of the missing stamp, but in the end they seemed to decide it was ‘okay’ after numerous people looked at my passport. I have a one year visa, and am unlikely to return on it, I will have to see if this bites me on return to China some time in the future...