Aeroplane Monthly did an in-depth article about the Rapide earlier this year, which mentioned IAS. The airline was started by Monique Agazarian.
G-AGJG, the aeroplane at Duxford, has now flown painted in wartime BOAC colours and looks very nice! I recall it at Biggin in the mid-70s painted purple and decidedly dilapidated!
Here's a kit of one of their Rapides a friend of mine built:
link
Treadders