can a 747 depart full of pax and full of fuel to go the distance
Yes. That's an old mantra from the days of the B747-100 at PIK. The B747-400 that VS use would not be at MaxTOW with freight and is a much more powerful beast.
It's wishful thinking. The meetings might be about ongoing fees for circuit bashing rather than moving the Glasgow operation South to Ayrshire.
It would be like miving from Orlando to Sanford, which they're not doing either.