Agree with the previous poster that the key to this is the photo in the AAIB report (clearly not chosen at random) and the statement that they have photographic evidence to show the cowls were not closed. Further, the recommendation is aimed at Operators, not Airbus, suggesting the AAIB have a view as to who needs to raise their game.
If the picture is representative, all the stuff about the need to crouch or lie down to see the latches is not germane to this incident.
The AAIB photograph is purely representative. As a multi licensed and type rated aircraft engineer who has opened and closed the cowlings on this particular engine type more times than I care to remember, I can tell you categorically that the fan cowls can be in one of two positions when closed but unlatched.
The first instance is as shown in the AAIB photograph. This picture clearly shows the cowlings proud of the inlet cowl and thrust reverser translating cowl. There is a noticeable gap which is clearly visible when you are standing close to the engine and I find it very hard to believe that the flight crew would have missed it during their PFI that particular morning. However, if the 'hold open' device attached to the bottom of the inlet cowl at the 6 o'clock position has been depressed as the cowls are closed, they will sit flush under the weight of gravity and appear secure. There will be no visible gap and unless the crew physically stoop down and look at the underside of the engine, they will have no way of identifying the 4 latches hanging in the breeze.
There is no design fault with these cowlings. When correctly closed and latched they will not come undone. The final report will no doubt reveal a multitude of circumstances and failings that led to this incident. I'm almost certain a lack of qualified manpower and excessive workload within the engineering department will be at the top of the list.