P5/3Z9DX operating in North Korea?

A Polish gentleman named Dom Grzyb has claimed to have operated recently as P5/3Z9DX from Pyongyang, the capital of the DPRK, more commonly known as North Korea. Earlier in 2015 I had read on the web about a proposed DXPedition to the DPRK and given the amount of interest this would generate in the ham community I kept my eyes and ears open to any further updates.
At the end of 2015 it was made known that Dom had in fact done some demo's to the North Korean authorities and had worked a number of stations as P5/3Z9DX.
There has been a lot of scepticism about the P5 operation with various individuals, including myself, doubting the veracity of some of the 'evidence' produced.
I had the pleasure of visiting the DPRK last September to avail of the opportunity to fly in some old Soviet era airliners, aircraft that have been long since banned from European skies.

This is one of the last passenger carrying Ilyushin Il-18's in service, a type produced in large numbers and sold widely.

I also flew on Air Koryo's last remaining airworthy Ilyushin Il-62 from Pyongyang to Samijyon and back on the same day after our visit to Mt. Paektu.

During our briefing the evening before departure from Beijing we were told, amongst other things, that we could bring our mobile phones into the country but we would be unable to access the local network. We were never made aware of any North Korean network that we could access by buying a SIM. Given their need for foreign currency it seems strange that we weren't offered this service, no matter about the cost it just seems strange to me that Dom was able to access the 'Koryolink' network.
I don't doubt that he visited the DPRK when he claimed he did but I doubt very much that he would have been granted permission to operate from any site within North Korea. If he had been granted permission I'm sure it would have been very well publicised in advance of his visit.