MB, I don't disbelieve you but do you mean the actual speed - not the trend arrow - actually settled below VLS and the A/THR did nothing? Or was it only below VLS for a split second in a gust or just very slow to correct?
Actual speed below, well below VLS, and lasting for several seconds of unresponsive A/THR. PM says "speed", now… What do you answer? "Don't tell me, tell to the A/THR". So in the end the only answer is that you have go around. You can't fix it, if you take over manually Airbus is saying somewhere that you should have done that before 1,000 ft, and you have the stabilized approach criteria to meet. There are too many restrictions, so just go around and send the bill to Toulouse.