AFAIK predictive windshear mainly detects wx-related (eg TS activity) windshear as it uses the wxradar.
It doesnot detect windshear that occur in "regular" strong wind conditions (as are produced by pressure differences), for instance windshear that is produced on short finals (27R?) LHR due to hangars or short final 27 AMS over the park.
As I understand that the weather was windy but without TS, it seems to be another journalist wind-up (or at least misinterpretation of an official statement).