That's an interesting point. He held a class 1 but had an OML restriction on that, though the CAA offered him initially a class 2 instead of renewing his class 1 with restriction. My understanding is you cannot put an OML restriction on a class 2 and suggested he may be able to fly single crew if he downgraded to a class 2 as offered. This though seems strange.
He is a wealthy businessman who would always fly with a safety pilot but wants to be able to fly legally 'single crew' in a King Air.
Just seems strange that he couldn't fly the King Air single crew on his restricted class 1, but it would appear he could fly on a class 2 single pilot.