SteveB has very kindly sent me scans of the Aeromilitaria article.

It seems that the 120-plus aircraft is a slight exaggeration – none of the operations landed more than about 36 at Great Sampford – although in terms of total aircraft including tugs it’s not too far off for the rehearsals for the Rhine crossing. These included Hamilcars, but these were released over their home bases to avoid having to recover them. Slightly bizarrely, one Horsa intended for Great Sampford ended up at Hethel – heaven only knows how!

And – aeronut will be pleased to hear this – retrieval was by Dakotas of 5 Heavy Glider Servicing Unit’s Glider Rescue Pool.

Finally, it turns out that the airfield on the briefing board is Earl’s Colne – should have checked when I looked up Rivenhall, as they are only a couple of miles apart.

Thank you for the help – it’s much appreciated – and thank you to Pondskater for the reference for the ORB. Methinks a trip to Kew is called for…

Adrian