Was "going to ask him". Are you now going to confirm he was never actually asked if he wanted 7000 or 9000? Why wasn't he given this option?
You say " to impatient to wait for a clearance". How do you know that he wasn't concerned about how he was going to hold outside an invisible line in the sky?
He had no DME. How would have you held OCTA in that case?
If they did everything they could to help him out why didn't they at any time direct him onto a frequency where the operator actually had a radar screen?
At all times all communication was to a radio operator that had no idea what direction the aircraft was heading.
Did you note that BASI never mentioned this important point? If he had been on a radar frequency the pilot would have been told nearly 30 minutes earlier he was heading in the wrong direction.
Probably still be alive today!