Have just seen it twice 5 mins ago 13.05Z local.
First time it had a noticeably different engine tone from other western aircraft as it slowed and descended from the west over SW London, however as it passed by on the 27L ? approach it was as quiet or quieter than a lot of the baby buses. Noticeable too was the gap behind it and the next aircraft, an BA 319, approx 5 mins due to wake vortex considerations, after all you wouldn't want those passengers shaken but not stirred
the model is about the size of a 737, and specifically designed to only just fit into the hold of an AN124
I wonder how much the 'model' weighs ?
Regards
SHJ