If I remember rightly, and I was at a presentation on improving ATC safety in Europe attended by at least one crew member of the British Airtours 707 which was following and monitored G-BDAN, the crew of the 707 listening to the instructions to G-BDAN were equally as confused as to what the instructions really were meant to achieve and, even before the ominous silence from G-BDAN had decided to request a diversion - which they promptly demanded when it became clear G-BDAN was down.
Many CRM lessons were learnt but there was more than one crew concerned and confused by those instructions that day.
BTW was Red Whelan the 727 driver who wore a baseball cap and regularly waved to spectators at MAN?