A33Zab,
Thanks for producing, as usual, such superb pictures (and apologies for my late acknowledgement).
This is a much more subtle mod than I had imagined. The 1960s VC10 AoA probes, which were dedicated to its three-stage stall protection system, enclosed the (much smaller) vanes completely. Slots in the cones admitted the airflow. The VC10s smaller sister, the BAC 1-11, employed a similar stall protection system. However, the (larger) vanes of its AoA probes were not enclosed.
Reviewing the big picture, it does seem strange that Airbus aircraft have latterly been experiencing so many problems resulting from icing of pitot probes, and now AoA probes. After all, these aeroplanes are operating in a similar environment to other types, and (presumably) jet airliners generally since even I was wearing short trousers. Granted, these FBW types are much more reliant on the availability and accuracy of the data concerned than previous types, most of which didn't even have AoA probes. If the heated AoA probes on my VC10 had become frozen, I might have been none the wiser unless I was pushing the buffet margins and waiting for the auto-ignition lights to flicker. But I flew the A320 for the first 14 years of its operation, and probe icing didn't seem to be an issue. Were we simply living in blissful ignorance?